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Discussion Starter #1
Hey guys. I'm sure this has been addressed but there are so many different responses to these questions I wanted to ask specific to my car.

'02 GTI, 1.8T, 5 Speed, AWP code

I've been getting a CEL for Random Misfire as well as a Misfire on each individual cylinder. When I read the codes though, sometimes it's Random Misfire, sometimes it's this cylinder or that cylinder, sometimes it's all the cylinders. There isn't any real consistency to the code other than that they're all some sort of Misfire codes.

Other than a little bit of a lumpy idle, the car runs great. Even with the CEL illuminated, it runs well. And the CEL is constant, not blinking.

I've replaced plugs, coils, coil pack wire harness, cam position sensor, coolant temperature sensor. Still trips the light as described above.

On a whim, I unplugged the MAF this morning before leaving for work. I drove to my office, about 10 miles, and the car ran fine. There was no change from how it ran with the MAF plugged in. However, I have never gotten a code for the MAF being bad.

I'm just curious after what I described if you guys think it could be my MAF that's causing my misfire codes?

Any input is appreciated. Thanks in advance.
 

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Discussion Starter #3
Standard mis codes. P0300, P0301, P0302, P0303, P0304.
 

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Discussion Starter #4
Also throwing a lean code P 0171 I believe and a high idle code P0507 I think. Pretty sure these are because of the SAI & PCV deletes though.
 

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Discussion Starter #5
Nobody else? Figured the technical forum guys would be all over this.
 

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Discussion Starter #8
I am running brand new stock plugs. Bought them, 4 new OEM coil packs and a new coil pack wire harness all from ECS.
 

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Discussion Starter #10
I'll double check the gap on those new plugs. I don't remember what i gapped them to, I kind if remember reading somewhere that they were suppose to be .040" but I could be imagining that too.

Coil pack wire harness is brand new, just replaced it a few weeks ago thinking it was my problem.

Thanks, I'll post back about the gap.
 

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Discussion Starter #12
I may be wrong about that .040" number. (I have a few cars). I'll double check the gap.

Any thoughts on the MAF? Like I said, it ran exactly the same unplugged. Bad MAF too? (Even if its not the cause of my misfire code)
 

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No; that's just confirmation that the car is running in open loop.

These ECU's revert to open loop operation whenever readings don't jive. It could be anything; including the maf, but it's just as likely something else.

The copper plugs work best; when used at the correct gap, and temperature range. Turbo cars like copper plugs.

You should be running ngkbkr7e plugs gapped at .028
 

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Checked your compression? Vac leaks? Start simple THEN throw parts at it...
 

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Discussion Starter #15
Thanks guys. Did check compression, numbers were pretty solid. Mid 160's to mid 170's across the board.

I ordered the plugs and coil packs from ECS, bought their OEM kit. Came with NGK plugs with the Audi and VW logos on them.

Checked, checked and then rechecked for vacuum leaks, couldn't find anything. So then I checked again with a bottle of carb cleaner, still no leaks.

This damn thing is driving me crazy...
 

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Time for vcds reading. Odb readers won't show intermittent issues except for expensive Ones.


Sent from my DROID RAZR HD using Tapatalk 2
 

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Thanks guys. Did check compression, numbers were pretty solid. Mid 160's to mid 170's across the board.

I ordered the plugs and coil packs from ECS, bought their OEM kit. Came with NGK plugs with the Audi and VW logos on them.

Checked, checked and then rechecked for vacuum leaks, couldn't find anything. So then I checked again with a bottle of carb cleaner, still no leaks.

This damn thing is driving me crazy...
You have to pressure test it. Spraying carb cleaner won't do you any good. These ECU's are fickle, and many times the leaks don't 'open up' unless you're under boost.

Use one of the sticky methods at the top of the forum.
 

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Discussion Starter #18
Cool, thanks guys. Looks simple enough, I'll try testing that way.

Assuming I find a leak somewhere behind the MAF, would a leak like that throw misfire codes?

And it does have a lumpy idle. So you guys very well may be on to something here.
 

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Whether its your problem or not; I pretty much guarantee that you'll find at least a couple small leaks when you pressure test.

Also clean your iat sensor, set your plug gap to .032 (stock) .028 (chipped) and get yourself at a solid baseline for proper diagnosis:beer:
 
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