# Stall with intermittent 16555 - Fuel Trim; Bank 1: System Too Lean code



## RobertH (Aug 27, 2006)

*Stall with intermittent P0171 code*

My Daughter’s 98 Beetle sometimes stalls on her when she is taking off. It’s an auto Trans… This happens about once a week and it’s after the car is warm. The car will stumble on her as she is taking off (usually at an intersection) and die. All she has to do is turn the car complexly off and restart and it works fine. She is also getting an intermittent P0171 code (Fuel Trim,Bank1 System too Lean) that I haven’t been able to tie directly to the stall problem because she doesn’t remember if it was on before the stall or not.
Assuming the two are related, she could have a severe vacuum leak (bad enough to cause a stall) that is intermittent. If not a vacuum leak, then something that is causing a lean condition, intermittently, that clears itself when the care is restarted. 
After reading http://wiki.ross-tech.com/index.php/Fuel_Trim_Info I monitored Group 32 and got -18 in the first field “fuel trim at idle” and 7 in the second field “fuel trim at elevated engine speeds”.
From the link - “Negative values indicate that the engine is running too rich and oxygen sensor control is therefore making it more lean by reducing the amount of time that the injectors are open.” I’m a little confused by that statement because P0171 indicates a lean condition but the negative value indicates a rich condition.
So the information I have is:
Intermittent stall, when taking off
Intermittent P0171 code (Fuel Trim,Bank1 System too Lean)
Only occurs when the engine is warmed up (but doesn’t happen that often)
Idle trim Lambda is -18% indicating a rich condition being corrected
I cant find a vacuum leak

Any Ideas
Also Is there a list of all the Group codes you can monitor with the VAG-COM, I was scrolling through and found some interesting data like four voltages (group 26) that vary with rpm (injector related?) but I don’t have a reference for the info…


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## RobertH (Aug 27, 2006)

*Re: Stall with intermittent P0171 code (RobertH)*

There was another incident today. She described it as at first she was accelerating and the car would not go above 45mph, but was revving high. It sounds as if it would not shift to a higher gear… By the way we often get the DTC: Address 1A (AutoTrans) – No Fault Code, and have had some shifting problems so that may have nothing to with the stalling/misfire problem. She slowed down and the car started bucking when she tried to take off again. The problem cleared and worked fine for a bit. About 5 min later the car started running rough (misfiring) and she stopped. Trying to take off she experience the same symptoms as before except after restarting the car and taking off the engine made a rattling sound and had no power. She stopped the car and it stalled and would not restart. 10 min later the car started fine and I drove it home with no problems.
At home I checked the DTC and found:
P0171 Fuel Trim,Bank1 System too Lean
P0300 Random/Multiple Cylinder Misfire Detected
P0302 Cyl.2 Misfire Detected
P0303 Cyl.3 Misfire Detected
“fuel trim at idle” = -18 
“fuel trim at elevated engine speeds” = 13.3
I think the rattling sound correlates to the misfire DTCs


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## [email protected] (Jun 5, 2002)

*Re: Stall with intermittent P0171 code (RobertH)*

6) When posting questions involving trouble codes, post the complete code(s), and the text that comes with them - both lines. Do not omit anything, and don't drop any digits, not even a leading zero! Make sure to mention which controller (Engine, ABS, etc.) had the fault code(s).
http://forums.vwvortex.com/zerothread?id=1201719


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## RobertH (Aug 27, 2006)

*Re: Stall with intermittent P0171 code ([email protected])*

Sorry, this is the data from VAGCOM I believe these came from Control Module 01- Engine
Sunday,24,June,2007,21:04:48
VAG-COM Version: Release 607.2-UD
Control Module Part Number: 06A 906 018 AB
Component and/or Version: MOTRONIC M5.9.2 AT V06
Software Coding: 00001
Work Shop Code: WSC 00066
7 Faults Found:
16555 - Fuel Trim; Bank 1: System Too Lean
P0171 - 35-00 - -
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16687 - Cylinder 3: Misfire Detected
P0303 - 35-10 - - - Intermittent
16686 - Cylinder 2: Misfire Detected
P0302 - 35-10 - - - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16687 - Cylinder 3: Misfire Detected
P0303 - 35-10 - - - Intermittent
16686 - Cylinder 2: Misfire Detected
P0302 - 35-10 - - - Intermittent


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## [email protected] (Jun 5, 2002)

*Re: Stall with intermittent P0171 code (RobertH)*


_Quote, originally posted by *RobertH* »_VAG-COM Version: Release 607.2-UD

That version is old, you should download and install Release 704.1 from our website:
http://www.ross-tech.com/vag-c....html
Have you tested your MAF per the instructions on the page you linked?


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## RobertH (Aug 27, 2006)

yes I did and got 72g/s which is a little low I think
115hp * .8 = 92. I couldent realy hold redline at all, it was missing, as if I was floating a valve when I got close...
I will update the software, thanks


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## RobertH (Aug 27, 2006)

*Re: (RobertH)*

I updated the software and it seems to working fine. It has revealed nothing new however...


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## mesuky22 (Feb 20, 2003)

*Re: (RobertH)*

air flow meter!!!


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## RobertH (Aug 27, 2006)

*Re: (mesuky22)*

Thanks mesuky, but what makes you say that? the lowish air flow? the misfires?


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## RobertH (Aug 27, 2006)

*Re: (RobertH)*

My daughter and I swapped cars so I have driven the bug for the last two days. I kept my laptop in the car to check codes and reset the mil. The first day I could not reestablish the fault. However, yesterday we had temps in the low 90s (live in CT, USA) and I was able to trigger the fault a few times during the day. Every time the problem would clear after the engine cooled off a bit. The problem as I observed it was loss of power with light to heavy pinging but I was able to keep driving, just back off on the throttle. Sometimes I could just stop the car for a moment and things would be fine. The Mil came on each time the problem occurred. I saved codes, checked different measurement blocks and reset the mill after each event.
Codes received:
Tuesday,26,June,2007,16:23:46
VAG-COM Version: Release 607.2-UD
Control Module Part Number: 06A 906 018 AB
Component and/or Version: MOTRONIC M5.9.2 AT V06
Software Coding: 00001
Work Shop Code: WSC 00066
6 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16687 - Cylinder 3: Misfire Detected
P0303 - 35-00 - -
16686 - Cylinder 2: Misfire Detected
P0302 - 35-00 - -
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16687 - Cylinder 3: Misfire Detected
P0303 - 35-00 - -
16686 - Cylinder 2: Misfire Detected
P0302 - 35-00 - -
Readiness: 0000 1101
Sometimes the set would include 
16555 - Fuel Trim; Bank 1: System Too Lean
P0171 - 35-00 - -
I started running a log and monitored:
Group 11
RPM, Coolant temperature,	Intake air temperature, Ignition angle (actual)
Because the problem seems to be temperature sensitive…
Group 015 Misfire recognition 
Counter Cyl.. 1, Counter Cyl. 2, Counter Cyl. 3,	Misfire recognition
Group 032 Oxygen sensors learning values (maximum value) 
Bank 1 sensor 1 idle, Bank 1 sensor 1 partial load
(idle trim and off idle trim)
Observations of the logged data:
Checking to see if the problem was tied to coolant temp, the misfires triggered at 84, 79, 90, 73 and 76 degrees Celsius. This is pretty inclusive.
When the problem occurred the misfire counters for cylinder 2 and 3 would get many hits, 90-100 for example and cylinder 1 would get just a few.
With the misfires occurring primarily in cylinders 2 and 3, logically that should be isolatable to a item common to the two of them and independent of the other two cylinders like the coil or something with the fuel injection system. The coil was replaced about a year ago. I know this care uses the wasted spark type coil system but am not sure which ones are common…


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## mesuky22 (Feb 20, 2003)

*Re: (RobertH)*

i still would say air mass meter since you tested the air mass meter with the vag com and found it was below spec. second as we all know the air mass meter is a very very common problem, you also have a fuel trim code maybe caused by a vacuum leak or the air mass meter. 
if I was in your position i would swap coil packs from 2 and 3 to 1 and 4 to see if the code follows. if it dosent try spark plugs, and last injectors. 
have you replaced the coolant temp sensor to the updated green one??
if all else fails try the air mass meter


_Modified by mesuky22 at 8:17 AM 6-28-2007_


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## RobertH (Aug 27, 2006)

*Re: (mesuky22)*

i still would say air mass meter since you tested the air mass meter with the vag com and found it was below spec. second as we all know the air mass meter is a very very common problem, you also have a fuel trim code maybe caused by a vacuum leak or the air mass meter.
if I was in your position i would swap coil packs from 2 and 3 to 1 and 4 to see if the code follows. 
I will do that
if it dosent try spark plugs, and last injectors.
have you replaced the coolant temp sensor to the updated green one??
No, didn't know about that. I will look into that and swap it asap
if all else fails try the air mass meter still would say air mass meter since you tested the air mass meter with the vag com and found it was below spec. second as we all know the air mass meter is a very very common problem, you also have a fuel trim code maybe caused by a vacuum leak or the air mass meter.
Right, that makes sense I am chasing a vacuum leak now. I put it on another post because I didn't want to clutter this one too much. Probably should have kept it together.
http://forums.vwvortex.com/zer...id=28
Thanks


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## Oracle12345 (May 29, 2007)

Looks you are in for a tune up kit and/or fuel injectors and that should take care of the misfires.
Grab an multimeter and start testing the spark plug wires, Ingition suppressor(coil wire). Also check the fuel injectors.


_Modified by Oracle12345 at 3:56 PM 6-28-2007_


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## RobertH (Aug 27, 2006)

*Re: (Oracle12345)*

small world, I'm from Norwich CT, I shop at the Willi Coop weekly and my daughter just graduated from Windham Tech(Willi)


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## RobertH (Aug 27, 2006)

*Re: (RobertH)*

I swapped the plug wires at the coil but got a permanent missfire on #4. I think I somehow trashed the #4 wire... its bad even after the swap back. The plugs and wires were replaced 11 months ago. I have the old ones I can use to check the wire. 
Also, they sold me the wrong sensor for this car the pins in the replacement are smaller than the original and recessed much further.


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## Oracle12345 (May 29, 2007)

lol what dealership you go to?
Check ignition coil forget to add that as well and anything with the fuel system you should look at the fuel pump rela first. But the old wires arent a good test because they are most likely out spec so it want give the numbers you want. 
What car you got agian ill look up what the specs should be for the wires.


_Modified by Oracle12345 at 7:25 PM 6-28-2007_


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## RobertH (Aug 27, 2006)

*Re: (Oracle12345)*


_Quote, originally posted by *Oracle12345* »_lol what dealership you go to?
Check ignition coil forget to add that as well and anything with the fuel system you should look at the fuel pump rela first. But the old wires arent a good test because they are most likely out spec so it want give the numbers you want. 
What car you got agian ill look up what the specs should be for the wires.
_Modified by Oracle12345 at 7:25 PM 6-28-2007_

98 Beetle 2.0L


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## Oracle12345 (May 29, 2007)

http://forums.vwvortex.com/zerothread?id=1201806r
For the fuel trim error


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## Oracle12345 (May 29, 2007)

The rating for the spark plug wires should be printed right on the wires it self.
Im not sure about the igntition coil since my bentely since it doesnt cover it but for my jetta between terminals 4 and 15 its 3 to 4k and between 1 and 3 terminals where the electric connector goes its .5 to 1.2k. '
Pick up a hanes for your car and start testing with a multimeter.


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## RobertH (Aug 27, 2006)

wires and injectors check good. The #4 cyl problem was a burnt plug, must have done that while swapping coil leads








I swapped out the coolant temp sensor, so far so good but I'm waiting for hot weather before I get too excited


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## Oracle12345 (May 29, 2007)

a burnt spark plug will cause misfires


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## RobertH (Aug 27, 2006)

*Its back!*

This problem has reared its head again. It started again once the weather warmed up but doesn’t seem to be consistent in that regard, even with continued hot weather the problem has stopped again. I’m sure it will be back.
Codes:
Sunday,15,July,2007,18:13:09:24882
VAG-COM Version: Release 704.1
Robert Hatcher
Address 01: Engine
Control Module Part Number: 06A 906 018 AB
Component and/or Version: MOTRONIC M5.9.2 AT V06
Software Coding: 00001
Work Shop Code: WSC 00066
9 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected 
P0300 - 35-10 - - - Intermittent
16687 - Cylinder 3: Misfire Detected 
P0303 - 35-10 - - - Intermittent
16686 - Cylinder 2: Misfire Detected 
P0302 - 35-10 - - - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected 
P0300 - 35-00 - -
16687 - Cylinder 3: Misfire Detected 
P0303 - 35-00 - -
16686 - Cylinder 2: Misfire Detected 
P0302 - 35-00 - -
16688 - Cylinder 4: Misfire Detected 
P0304 - 35-10 - - - Intermittent
16688 - Cylinder 4: Misfire Detected 
P0304 - 35-00 - -
16685 - Cylinder 1: Misfire Detected 
P0301 - 35-00 - -
Readiness: 0000 0000
Drove around while logging some data and noted the following looking at the data ina spreadsheet:
cyl 1 misfires the most, 68 times
cyl 2 and 3 misfire together most of the time 35 and 54 times respectively
cyl 4 misfires the least, 13 times, with others or independently
At first on cyl 1 misfired but after a few minutes it tapered off and 2 and 3 were predominate
Although plotting RPM vs misfires revealed no direct relationship to acceleration or speed to the misfires the following is true: 
cyl 1 lowest misfire RPM is 1400 
cyl 2 lowest misfire RPM is 1960
cyl 3 lowest misfire RPM is 1920
cyl 4 lowest misfire RPM is 1800 
No misfires below 1400 RPM
Most misfires occur between 2000 and 3000 rpm
During the MAF test up to 6080 RPM all cylinders misfired at least once the G/S was 72

MAF vs Misfires:
cyl 1 lowest MAF level that misfires is 6.46
cyl 2 lowest MAF level that misfires is 11.67
cyl 3 lowest MAF level that misfires is 10.83
cyl 4 lowest MAF level that misfires is 7.5
Plotting the data you can almost draw a line splitting the cylinder 1 vs cylinder 2/3 data. Most cylinder 1 misfires occurred below 12 g/s and most of the 2/3 misfires above 12 g/s
Trim is at -18, Idle and 7, Part Load value
I'm still pondering


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## Oracle12345 (May 29, 2007)

Wow sounds like you got yourself quite a problem. It could be something above your head and may need to see a dealership. 
Only a shot in the dark but something could be wrong with your ecu. If you have the bentely manual they tell you how to see if the computer is faulty. 
-Does the car run like **** or does it seem fine?
-Also might want to do some google searching and see if they are websites similar to this one and has vw techincans more willing to give up thier knowledge.


_Modified by Oracle12345 at 7:13 PM 7-22-2007_


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## RobertH (Aug 27, 2006)

*Re: (Oracle12345)*

it runs fine except when its acting up, its intermittent. 
I just purchased a bentely manual so I'm using it now.


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## owain1602 (Jun 15, 2006)

Sounds very much like an Air mass meter, what does the altitude correction factor say?


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## RobertH (Aug 27, 2006)

*Re: (owain1602)*

Ill check that. I keep thinking its the MAF myself but I get held up because it cyl 2 and 3 misfire much more than 1 and 4. I would think that an MAF problem would effect all of them about the same. But I am not a slave to logic


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## mesuky22 (Feb 20, 2003)

*Re: (RobertH)*

you still didnt try the air mass? my money is still on the MAF.


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## RobertH (Aug 27, 2006)

*Re: (owain1602)*

what should I expect from the altitude correction factor, whats good, whats bad?


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## RobertH (Aug 27, 2006)

*Re: (RobertH)*

MAF replace, still have problem.


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## RobertH (Aug 27, 2006)

*Re: (RobertH)*

The saga continues:
Replacing the MAF did not clear the misfire problem but it does appear to have been needed. The MAF test now reaches 94 g/s vs to original reading of 72. The altitude adjustment climbed down from 10.6 to 0-3.4 (moves around a little). It seems to take a little more load to cause the misfire problem. But that could be a self justifying deception 
An update on the problem:
Occurs after the car is warmed up (I’m going to confirm this tomorrow morning by trying to force the problem when the car is cold)
Primarily misfires on cylinders two and three
Minor event
Sometimes it’s just on harder acceleration and inconsistent.
Can aggravate the problem (make it happen easier) by running the AC i.e. higher load
Worst case
Pings a lot 
The car will slow down and not accept any load. Will idle but can’t take off and will stall out. When it’s real bad the engine cannot be revved up from idle, it will stall unless the throttle is opened slowly. Trying to rev the car, it sound like a carbureted car with a bad accelerator pump, it has that starved WOAAAT sound, and it pings. A very lean sounding problem. However the fuel pump and pressure regulator pass testing.
It’s as if something hangs and once the car sits for a while (cools?) the problem clears.
Another thing I notices is that the fuel trim values have changed dramatically after the last MIL reset
“fuel trim at idle” = used to be -18 is now -1.8 
“fuel trim at elevated engine speeds” = used to be 13.3 is now 0.0

The codes are:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16687 - Cylinder 3: Misfire Detected
P0303 - 35-00 - -
16686 - Cylinder 2: Misfire Detected
P0302 - 35-00 - -
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16687 - Cylinder 3: Misfire Detected
P0303 - 35-00 - -
16686 - Cylinder 2: Misfire Detected
P0302 - 35-00 - -


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## RobertH (Aug 27, 2006)

*Re: (RobertH)*

It turned out to be the coil causing the misfires. 
To isolate the coil I swapped the 2 banks by swapping plug wires one with two and three with four and the coil inputs from the ECU. The misfires moved from cylinders 2 and 3 to cylinders 1 and 4 as recorded with VAG-COM. 
With the replacement coil installed the problem has not reoccurred. Fortunately it was withing the 1 year warranty so it was free of charge. Unfortunately it the BERU model which I read lots of complaints about. If this on acts up Ill just by an OEM next time. 
Notes on the test:
Swapping the inputs from the ECU, there is one lead for each bank on pins 1 and 3 of the plug that attaches to the side of the coil. I swapped the inputs by removing the tape from the harness, clipping both leads and installing bullet connectors on the leads so that I could swap them back and forth if necessary to confirm results.
With the coil leads swapped and the ECU inputs swapped, plugs 1 and 4 are running on the 2-3 coil bank and plugs 2 and 3 are running on the 1-4 coil bank.
Double check a wiring diagram for the pin numbers and wire colors. The diagrams don’t indicate what lead controls what bank but they are the only two leads on the plug that come from the ECU, the other two leads are 12V and ground. WARNING Don’t try and run the car with just the coil leads swapped the engine will not run and you may damage something.
Clipping the leads is not something I would normally do but in this case I needed good evidence. I will probably butt splice the wires and heat shrink them now that I'm done.
Thanks for all the support


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## RobertH (Aug 27, 2006)

*Re: (RobertH)*

With the replacement coil installed the problem has not reoccurred. Fortunately it was within the 1 year warranty so it was free of charge. Unfortunately it the BERU model which I read lots of complaints about. If this on acts up Ill just by an OEM next time.


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## Mile High Assassin (Aug 28, 2002)

*Re: (RobertH)*

Unplug your MAF and see what happens. That should cause an extremely RICH (and safe) condition.
When is the last time you changed the fuel filter? (I know VW says the filters are lifetime on many cars but if you got bad fuel.... )


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## RobertH (Aug 27, 2006)

*Re: (Mile High Assassin)*

"Unplug your MAF and see what happens. That should cause an extremely RICH (and safe) condition."
Thanks for posting, what will that tell me?


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## Mile High Assassin (Aug 28, 2002)

*Re: (RobertH)*


_Quote, originally posted by *RobertH* »_"Unplug your MAF and see what happens. That should cause an extremely RICH (and safe) condition."
Thanks for posting, what will that tell me?

If that gets rid of your lean condition then your MAF is to blame. I know you replaced it already but I have seen bad MAF's shipped as replacements.
I dunno thinking on it some more....
IF your MAF was bad I think you would be running rich because the car would go into a safe mode. 
The MAF is more than likely NOT the problem. I would still try what I suggested to see what it does change. 
Edit... it was late last night.

I don't think it was a MAF for you typically see rich conditions with a failing MAF.
O2 Sensors are not out of the question.
I would think about replacing your plugs. If nothing else start with re-torquing them down to spec (sorry I don't know what spec is on a 2.0).
Not trying to pimp a product but I have had a set of Neuspeed 2.0 spark plug wires laying around my garage in a box since 2002 when I sold mine. If you want them shoot me an offer. I have no idea what they are worth they have about 1 years worth of use on them.
I have also heard of the 2.0 having some injector issues. I don't know much about it but you might see what you can find on here about it.



_Modified by Mile High Assassin at 4:07 PM 7-31-2007_


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## RobertH (Aug 27, 2006)

*Re: (Mile High Assassin)*

Since replacing the MAF I have not seen the lean code and the trims are -1.8 and 0.0 so I think that took care of the lean issue (unless you see something I am missing). I'm hoping the coil solved the misfire problem but I need to wait a few days to make sure.
Plugs and wire are >1 year out and pass visual inspection. Wire pass resistance test. If the wires pass resistance can they still cause misfires? Ive never seen it but then VWs seem to be ultra sensitive...


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## Mile High Assassin (Aug 28, 2002)

*Re: (RobertH)*


_Quote, originally posted by *RobertH* »_Since replacing the MAF I have not seen the lean code and the trims are -1.8 and 0.0 so I think that took care of the lean issue (unless you see something I am missing). I'm hoping the coil solved the misfire problem but I need to wait a few days to make sure.
Plugs and wire are >1 year out and pass visual inspection. Wire pass resistance test. If the wires pass resistance can they still cause misfires? Ive never seen it but then VWs seem to be ultra sensitive...

*I* would think you are alright with the plugs and wires.


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