# Symptoms of a faulty MAF



## chiltonRabbit (Feb 14, 2009)

So I'm having problems with my car bogging on acceleration (misfire). Last year, around march, my car had the same symptoms and the mechanic replaced my MAF with a new one (or so he says). And I didn't have a problem ever since till early this year.
I can hear the fuel pump prime, changed the fuel filter, changed the spark plugs, replaced coolant sensor, and did a compression test. Recently I tried cleaning the fuel injectors by running carb cleaner through it while providing 6V to get it to open. Ever since then the problem seemed worse. I did, however, take off the secondary air pump, remove coils, remove spark plug wires, remove upper intake, replaced a few hoses, and removed the intake duct/w MAF as well.
The car bogs when accelerating (in second gear 2500-3000 rpm) and I'm getting misfire codes. I wanted to test the MAF, but read that I need some special equipment to test it out. I tried unplugging the MAF and drove without it only to have the same problems occur. Would this mean my MAF is bad? (by the way the CEL didn't go off when I drove it)
If I have to replace it I'm thinking of getting the MAF from europartsdirect.com for $84. The part # BSH017411. Does anyone know if this one is any good or is it the one that tends to go bad?


----------



## 97VWJett (May 17, 2003)

*Re: Symptoms of a faulty MAF (chiltonRabbit)*

Which cylinders are misfiring? Did you swap injectors or plugs and see if the problem follow a particular cylinder? Are the plugs gapped right?
A bad MAF will not necessarily cause a misfire. The MAF is there to read how much air. If the computer doesn't know, it will assume a default amount of air is coming in and that is why the car runs with it unplugged and the CEL would be on for an open circuit for the MAF.


_Modified by 97VWJett at 9:06 PM 3-11-2009_


----------



## chiltonRabbit (Feb 14, 2009)

*Re: Symptoms of a faulty MAF (97VWJett)*

My car was taken to a mechanic earlier this year with this problem and the error codes were:
P1225 - Fuel Injector Circuit, short to ground (cylinder no. 1)
P1226 - Fuel Injector Circuit, short to ground (cylinder no. 2)
P1227 - Fuel Injector Circuit, short to ground (cylinder no. 3)
P1228 - Fuel Injector Circuit, short to ground (cylinder no. 4)
P1451 - Secondary Air injection system, pump relay circuit short to ground
P1421 - Secondary air injection valve circuit, short to ground
P1425 - Fuel tank vent valve circuit, short to ground
P1472 - EVAP system leak detection pump circuit
P0102 - Mass Air Flow sensor circuit, low input

They said the problem was a vacuum leak replaced the vacuum booster hose. Two days later the car still has bogging problems on acceleration along with error codes.
I erased the codes and drove around and the CEL would go off (twice). The error codes were:
P0303 - Cylinder no 3 misfire detected

P0300 - Random/Multiple cylinder misfire
P0301 - Cylinder no 1 misfire detected
P0303 - Cylinder no 3 misfire detected
The plugs are brand new and don't need gapping. I haven't tried swapping the injectors. 
You think the injectors are clogged? I cleaned them out with carb cleaner. Maybe it wasn't good enough?


----------



## WindsorBlueJustice (Jul 16, 2004)

*Re: Symptoms of a faulty MAF (chiltonRabbit)*

bump because I'm having almost identical problems. I already replaced the coil & plugs and everything in between.
FWIW, my codes were P0300, P0302, & P0303


----------



## vwcabman (Jun 13, 2008)

*Re: Symptoms of a faulty MAF (WindsorBlueJustice)*

i had this same exact problem over the summer bogging in the same rev range as you and i found that it was the spark plug wires so i replaced the plugs and wires after doing this it bogged way less to fix it completely i went to radioshack and bought electrical cleaner that leaves no residue and i uninstalled the maf and sprayed it down then i disconnected the negative terminal on the battery for 10mins and plugged it all back up and started the car and let it idle for 10mins and presto my car does not bog anymore from 2k to 3k. also it may be a good idea to remove the distributer cap and lean everything inside of it with a towel sometimes dew can build.


----------



## slo_VDub (Feb 18, 2006)

Same problem here...After replacing the coilpacks and spark plugs I'm still misfiring after 3-4 minutes of driving. I reset the codes via VAG-com and it will idle beautifully in the driveway. I replaced the ICM last summer when I had this same problem and will be ordering a new one Monday. Hopefully that will take care of the problem...will be checking back to this post to see what helps anyone else.


----------



## MecE2.0 (Dec 20, 2005)

*Re: Symptoms of a faulty MAF (chiltonRabbit)*

check spark plug gap, spark plug wire continuity, give your coil pack a mist (look for arcing).


----------



## chiltonRabbit (Feb 14, 2009)

*Re: Symptoms of a faulty MAF (MecE2.0)*

I've tried misting my spark plug wires and coil pack, but didn't notice any arcing. 
I just replaced my spark plug wires today and fixed the misfiring issue.








My old spark plug wire (for cylinder 3) did seem somewhat loose. It didn't click whenever I took it off/on the spark plug. Didn't realize it would make that big a difference. 
My MAF was actually replaced last year. I checked it again and it looks dirt free, so I haven't tried cleaning it. So if the MAF was bad the symptoms it would have would only be a car that was running rich? If the car was bogging on acceleration then it would have to be something else, right?


_Modified by chiltonRabbit at 6:30 PM 3-23-2009_


----------



## Kracker (Apr 27, 2004)

*Re: Symptoms of a faulty MAF (chiltonRabbit)*

P1225 - Fuel Injector Circuit, short to ground (cylinder no. 1)
P1226 - Fuel Injector Circuit, short to ground (cylinder no. 2)
P1227 - Fuel Injector Circuit, short to ground (cylinder no. 3)
P1228 - Fuel Injector Circuit, short to ground (cylinder no. 4)
P1451 - Secondary Air injection system, pump relay circuit short to ground
P1421 - Secondary air injection valve circuit, short to ground
P1425 - Fuel tank vent valve circuit, short to ground
P1472 - EVAP system leak detection pump circuit
P0102 - Mass Air Flow sensor circuit, low input,
if you have all these codes together , sounds like a fuel pump relay.
as for the missfires, try swapping the injectors ,
I'm going with you have an early mk4 , the fuel pump relay also controls almost everything you listed 

_Modified by Kracker at 8:01 PM 3-24-2009_


_Modified by Kracker at 8:05 PM 3-24-2009_


----------

