# Misfire under load/boost...



## PjS860ct (Dec 22, 2002)

just happened a few weeks ago when my 01 gti 1.8t started to misfire under full boost/load on high gears... (i dyno'ed it on 1-16-08 and it was fine) 

-car still start up fine and idles @ ~ 750-770..
-boost gauge read at -21 @ idle.. decel @ -21..
-still drives normal, *no* jumpy idle, does *not *stall..
-holds boost, spikes up at 22psi holds 17 ...down to 12 @ redline but slow








and *it only hesitates when i go WOT*...








spark plug ngk7's @ .028 done 4 months ago
chip/intake/exhaust/ko4-001...etc
VAG'ed it and it has..
-p1128, lean code
-p0300-35-10 random misfire 
-p0304-35-10, misfire on 4
-p0302-35-10, misfire on 2
-p0571-35-10, brake light switch signal









goin to work on the car this weekend, and wondering what should i check first... plugs, coils, wires, maf...

thanks in advance! http://****************.com/smile/emthup.gif
























guilty party^


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## themachasy (Jan 28, 2006)

*Re: Misfire under load/boost... (PjS860ct)*

Theres a recall on your brake light switch, and the others sound like the coilpacks are on their way out. How many miles are on the plugs?


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## PjS860ct (Dec 22, 2002)

*Re: Misfire under load/boost... (themachasy)*

less than 3000 miles on the plugs... yep, i know about the recall but cant afford to not have my car for even a day, (_ill just buy the $5part and install that myself_... )vrt is in service








does the hitachi bolt down coils plugs right in the AWW coilpack harness?
http://****************.com/smile/emthup.gif








thanks.. 


_Modified by PjS860ct at 8:28 AM 3-6-2008_


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## bpfoley (Nov 30, 2000)

*Re: Misfire under load/boost... (PjS860ct)*


_Quote, originally posted by *PjS860ct* »_less than 3000 miles on the plugs... yep, i know about the recall but cant afford to not have my car for even a day, (_ill just buy the $5part and install that myself_... )vrt is in service








does the hitachi bolt down coils plugs right in the AWW coilpack harness?
http://****************.com/smile/emthup.gif








thanks.. 


Just go into the dealer and have it done, takes 30 minutes total. You say you can't afford to not have a car for a day, wait until someone rear-ends you.
Replace coil-packs.


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## RvGrnGTI (Apr 13, 2005)

*Re: Misfire under load/boost... (bpfoley)*

same symptoms as my maf sensor... i cleaned it up ( a few weeks ago ). i would hit 23 psi in the higher gears and it would bog out on me hardcore and get a blinking cel.


_Modified by RvGrnGTI at 7:42 AM 3-6-2008_


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## RoflsaurusRex (Nov 9, 2007)

*Re: Misfire under load/boost... (bpfoley)*


_Quote, originally posted by *bpfoley* »_
Just go into the dealer and have it done, takes 30 minutes total. You say you can't afford to not have a car for a day, wait until someone rear-ends you.
Replace coil-packs.

i agree... since its happening on more than one cylinder and the plugs only have 3k miles on them. might as well clean the maf while you're under the hood too.


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## passatrip (Jan 30, 2008)

*Re: Misfire under load/boost... (PjS860ct)*

Coilpacks!!! Same exact thing happened to me.


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## PjS860ct (Dec 22, 2002)

*Re: Misfire under load/boost... (PjS860ct)*

http://****************.com/smile/emthup.gif thanks everyone...


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## CesarinGTI (Mar 27, 2007)

*Re: Misfire under load/boost... (PjS860ct)*









just bought myself this today.... 
going to change my Oils on the weeekend, wash the filter and clean maf..
everything else has been done


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## PjS860ct (Dec 22, 2002)

*Re: Misfire under load/boost... (CesarinGTI)*

been busy all day today doin some maintenance on the gti...
i did..
- new ngk7 capped @ .030 (went a little wider gap)
- checked coils for cracks = found none
- cleaned the MAF and Air Intake temp sensor with the MAF cleaner = cleaner now








- wrapped coil pack wiring with electrical tape to keep moisture out = found some cracks and peeling wiring insulation...
- changed oil and filter
- checked the vacuum system = seems ok
- checked all clamps on hoses = http://****************.com/smile/emthup.gif 
- serviced DV valve = http://****************.com/smile/emthup.gif 
- washed car = http://****************.com/smile/emthdown.gif bc it rained after








i drove the car around and with a few WOT passes and it seems ok to me, but this was in the rain so cant realy go really fast...





























to everyone 
*edit*: drove it some more yesterday and today... WOT feels great again, no more hesitation @ WOT, pulls like before... http://****************.com/smile/emthup.gif 
only problem is i dont know wut fixed it bc i did i few things at once...








anyways










_Modified by PjS860ct at 7:34 PM 3-9-2008_


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## PjS860ct (Dec 22, 2002)

*Re: Misfire under load/boost... (PjS860ct)*

arggh!! i hate my car rite now!!








i was driving around today to test the car if it still misfire under load/WOT... and yea, it still doing it







now its alot worst, im actually thinking about trading it in, just bc i dont want to figure/worry this out anymore...
plus i think the clutch is slipping a little (in 5th gear, i stepped on the gas my the rpm went up, but not in lower gears)







and its not a stock clutch either








(just ordered the ecs stg1 clutch kit today, i guess im keeping it)








maybe i really have to change the *coilpacks* now and maybe the *maf*... argh!!







not in my plans, i have the vrt takin most of my money ... n the fiancee




















































_Modified by PjS860ct at 5:02 AM 3-16-2008_


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## PjS860ct (Dec 22, 2002)

*Re: Misfire under load/boost... (PjS860ct)*

also now, when i hit the gas there is NO power... then all of a sudden, ALL the power is back and im doing warp speed already





















.. has anybody dealt with this kinda problem? and figured it out...
O YEA!... forgot to add that my *check engine light does not light up* ever since i bought it, so i cant see if its flashing or not







can i see that with my vagcom(registered)?


thanks so much for helping










_Modified by PjS860ct at 4:08 AM 3-15-2008_


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## PjS860ct (Dec 22, 2002)

*Re: Misfire under load/boost... (PjS860ct)*

just bought d ecs stg1 clutch/flywheel kit to fix my slipping clutch ...n the hitachi e coils for my missing problem




































not in the plans but this is how it goes

















_Modified by PjS860ct at 5:57 AM 3-16-2008_


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## zeusenergy (Feb 25, 2008)

*Re: Misfire under load/boost... (PjS860ct)*

You said the coil wiring is cracked. This could do more than give you the symptoms you describe. After changing out the coils, if you still have a problem, you can change the coil pack harness out and try to insulate the new one from heat. This problem is common and can do anything from create hesitation, to eninge misfire codes, to the car not wanting to run at all


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## PjS860ct (Dec 22, 2002)

*Re: Misfire under load/boost... (zeusenergy)*

yep, the coil wiring is cracked, but in only a few places (on 1 and 3 coils) but thats not the coil that is doin the misfire))... not really that bad, so i wrapped the wiring individually with electrical tape... 
well ill see if the new coils i ordered fix this... i hope or im really trading this car in...hahaha


_Modified by PjS860ct at 6:03 AM 3-17-2008_


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## zeusenergy (Feb 25, 2008)

*Re: Misfire under load/boost... (PjS860ct)*

It still could be a harness issue. It's not that hard to change out if you have some time on your hands. Good luck my friend!


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## nicks03jettagls (Nov 28, 2006)

Do you by chance have the Diode mod? Or does your chip call for over 20psi spikes?
Which chip do you have?
Have you Lemmewinked it?
If you're running lean, on a k04, that's chipped with new coils and recent plugs:
Could be a fuel delivery problem (hence the lean)
Could be a MAP Problem causeing the missfires.
Could just be bad tuning by the Chip maker.
I was having the same problem with my k03s. On the dyno I was running 14.1 a/f till redline. Spiking at 18psi, dieing off at about 12 past redline.
I got a different chip, New Map, new plugs, (coils pretty new, only have 10k), Higher FPR, Had the fuel system cleaned including new fuel filter.
Now running 12.3:1 a/f ratio on the dyno. Spikes at 23 (no diod mod), dies off at 15psi at 7k rpm.
Just my 2 cents


_Modified by nicks03jettagls at 7:59 PM 3-16-2008_


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## PjS860ct (Dec 22, 2002)

*Re: (nicks03jettagls)*

...i have the dalhback chip
...new coils will be in when i get them from ecs... 
same with the clutch








thanks http://****************.com/smile/emthup.gif


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## jjgti18t (Apr 27, 2007)

*Re: (PjS860ct)*

Did you figure it out? Im having a similar problem, I just got the unitronics 1+ program on an AWP. Car rus great untill full boost when it starts to misfire. Low gears it does not happen. I switched to BKR7E gapped em to .028 and it helped for the low gears but its still misfiring in 5th gear at WOT. The program spikes at like 22 psi. some times I get a kind of limp mode where it wont boost more than 5 psi after it misfires.


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## rayblais (Nov 1, 2006)

*Re: (jjgti18t)*

too big of a gap on your plug can ruin coil packs


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## PjS860ct (Dec 22, 2002)

*Re: (rayblais)*

nope, still havent fix it yet...the hitachis bolt down coils r in but it still misfires... im still breaking in the clutch and all... so i cant really step on the car yet
now im thinking its the maf... ill be buying a used one here sometime or at fourseason n see wut happens...









... if not this car is getting parted and getting traded in

















_Modified by PjS860ct at 1:13 PM 4-7-2008_


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## jjgti18t (Apr 27, 2007)

*Re: (PjS860ct)*

I'm going to try a cleaning some stuff, MAF, TB etc. and gap the plugs to .025 I'll post here if it works. VRT Carat !?.. damn thats bad ass. I had a red carat back in the day with the old H.O. 8v, I loved that car.


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## PjS860ct (Dec 22, 2002)

*Re: (jjgti18t)*

unplug the maf this morning coming back home from work and it didnt misfire at all... ran awesome... ill plug it back in when i go back to work later today to double check... http://****************.com/smile/emthup.gif 
i guess i need a new maf


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## 27psigti (Feb 2, 2007)

*Re: (PjS860ct)*


_Quote, originally posted by *PjS860ct* »_unplug the maf this morning coming back home from work and it didnt misfire at all... ran awesome... ill plug it back in when i go back to work later today to double check... http://****************.com/smile/emthup.gif 
i guess i need a new maf
















same thing happened to me. car ran fine till i gave it alot of gas.Vag-com said cylinder 2 miss fire so i bought all new coils and plugs didnt help replace the maf runs perfect now.


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## Vegas337 (Jan 10, 2006)

Wow yeah I don't know what it could be. My GTI is misifiring also. It was misfiring at 10k miles and it is still doing it.


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## PjS860ct (Dec 22, 2002)

*Re: (27psigti)*

yep, i step ont the gas and it misfires... but mine misfires on all cylinders







new hitachi coils and plugs as well... no difference... will buy a new maf soon


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## 27psigti (Feb 2, 2007)

*Re: (PjS860ct)*


_Quote, originally posted by *PjS860ct* »_yep, i step ont the gas and it misfires... but mine misfires on all cylinders







new hitachi coils and plugs as well... no difference... will buy a new maf soon


im tell u its the maf my mechanic couldnt figure it out and hes the best vw mech around.nothing showed on vag-com but a misfire but after replacing the coils and plugs and it still did nothing.we where alittle stumped.So he had a maf laying around the shop we just said f it put it in and it ran fine.


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## PjS860ct (Dec 22, 2002)

*Re: (27psigti)*

good to know.. ill be ordering 1 today @ gap and it should be here by friday http://****************.com/smile/emthup.gif








i love germanautoparts.com


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## MrMatthew33 (Apr 14, 2006)

wow am i glad to see this post. i have been having this SAME issue for the past couple of weeks now. I was thinking maybe it could be my plugs and coils. by the looks of things now it might be the MAF. im gonna unplug my MAF today at lunch and see if that is the issue.


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## PjS860ct (Dec 22, 2002)

*Re: (MrMatthew33)*

ordered the maf, should be here tomorrow on my day off...  http://****************.com/smile/emthup.gif ill be back here for the good or bad news...







i hope it works bc if not its gonna get traded in for an evo8

















_Modified by PjS860ct at 8:09 AM 4-10-2008_


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## jjgti18t (Apr 27, 2007)

*Re: (PjS860ct)*

After Cleaning my MAF, using some good injector cleaner, changing the fuel filter and a .025 plug gap my missfire problem is 95 % gone. It only misses a little in fith gear at WOT after Ive been on it for a while and its pretty hot. Im just hoping that the chip is still adapting and it will go away eventually. I dont know if this helps, but it's nice to comiserate.
edit: I changed the coils and Its all good!


_Modified by jjgti18t at 1:22 PM 4-14-2008_


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## PjS860ct (Dec 22, 2002)

*Re: (jjgti18t)*

ups should have delivered it today... i dont know why they re-scheduled it till monday... argh!!!


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## ShockerWorthy (Dec 8, 2007)

*Re:  (PjS860ct)*


_Quote, originally posted by *PjS860ct* »_ups should have delivered it today... i dont know why they re-scheduled it till monday... argh!!!









UPS: Unexpected Postponement Shipping-happened to me too brother..
I replaced my coils, did nothing in terms of misfires as well (money wasted







) But ofcourse the MAF was the problem...such a simple fix but automatically we all assume its a problem of epic proportions...I almost want to congratulate you for fixing your car, but knock on wood bc until you have the MAF in its


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## PjS860ct (Dec 22, 2002)

*Re: (colabrese)*


_Quote, originally posted by *colabrese* »_
UPS: Unexpected Postponement Shipping-happened to me too brother..
















http://****************.com/smile/emthup.gif 
yea n i was home all day waiting for it, such a waste...
for now its unplugged running soo rich i can see my gas dissapear







but at least its driveable








yea... knock on wood! im getting to hate my car more everyday


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## MrMatthew33 (Apr 14, 2006)

I tried running my car with the MAF unplugged for a bit and it didnt help at all. does anyone think it could be the spark plugs or MAF?


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## PjS860ct (Dec 22, 2002)

*Re: (MrMatthew33)*

have you scanned it yet with vag com? do you have a boost/vacuum gauge? if yes, wut does it reads at idle? check your coil packs for cracks as well...


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## MrMatthew33 (Apr 14, 2006)

*Re: (PjS860ct)*


_Quote, originally posted by *PjS860ct* »_have you scanned it yet with vag com? do you have a boost/vacuum gauge? if yes, wut does it reads at idle? check your coil packs for cracks as well... 

Yeah i had it scanned and no codes came up at all. at idel it reads 20Hg...ill check for coil cracks in a bit...Thanks http://****************.com/smile/emthup.gif


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## Space9888 (Mar 18, 2002)

*Re: Misfire under load/boost... (PjS860ct)*

if you get a flashing engine light....... likely coilpack failure
change your fuel filter... ive had this same thing happen when not coils, 1 time it was the 02 sensor and 1 time it was the fuel filter. 



_Modified by Space9888 at 6:55 PM 4-14-2008_


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## project{Euro}Tune (Mar 25, 2008)

*Re: (jjgti18t)*

sounds like you've got a vacuum leak, this could be a dying 02 sensor if its missing under WOT mine was just doing that and i had the primary 02 replaced and it instantly fixed...car pulls like it should


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## PjS860ct (Dec 22, 2002)

*Re: Misfire under load/boost... (PjS860ct)*

*** *just changed the MAF sensor *a few minutes ago after i got home from work... then took it for a drive for about 5mins with the maf sensor plugged in... and [email protected]!!! *NO Misfire at all*!!! im crossing my fingers now and hoping that fixed the problem... http://****************.com/smile/emthup.gif
















so i guess it was the MAF sensor all along








_now it reads _
-22 @ idle 
-24 @ decel







































_Modified by PjS860ct at 3:23 AM 4-15-2008_


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## MrMatthew33 (Apr 14, 2006)

*Re: Misfire under load/boost... (PjS860ct)*


_Quote, originally posted by *PjS860ct* »_*** *just changed the MAF sensor *a few minutes ago after i got home from work... then took it for a drive for about 5mins with the maf sensor plugged in... and [email protected]!!! *NO Misfire at all*!!! im crossing my fingers now and hoping that fixed the problem... http://****************.com/smile/emthup.gif
















so i guess it was the MAF sensor all along








_now it reads _
-22 @ idle 
-24 @ decel






































_Modified by PjS860ct at 3:23 AM 4-15-2008_

Glad you got it fixed!







now im thinking if i should just change my MAF as well before i do anything else....


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## jjgti18t (Apr 27, 2007)

*Re: Misfire under load/boost... (MrMatthew33)*

Good to hear you wont be selling it for an evo. http://****************.com/smile/emthup.gif


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## rumpinho (Apr 14, 2008)

what should be the correct values for the boost gauge at idel and decel? 
-22 and -24 like he said?
I ask because I have some weird idle issues and want to know if everything is up to par...


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## rumpinho (Apr 14, 2008)

also how did you cleaned the MAF? could this be done with carb cleaner, or 99% proof alcohol?


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## PjS860ct (Dec 22, 2002)

*Re: (rumpinho)*

yes you can use both, but you can also find the real MAF cleaner at any parts store...








also yes, ive been thinking of getting rid of the car cus i wanted something better (choices were evo8, 350z and the s2000) but i guess those cars will be there after i pay this off in 2 years...







and i guess the my forsale threads will be deleted cus the vrt project will be continued as well http://****************.com/smile/emthup.gif










_Modified by PjS860ct at 2:23 PM 4-16-2008_


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## RipperMan (Feb 25, 2004)

*Re: (PjS860ct)*

holy moly! I have nearly the exact same issues! and have done nearly all the same things!!!
I even have the wriring harness issue...
Thank you VERY MUCH !! for posting your progress on this dude! you probably saved me a few thousand - ordering a new MAF now.
-Peter


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