mk4 gti 1.8t judder at WOT

buster

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mk1 Aud TiTy
My car has been off the road for nearly a year. I've started driving it again yesterday and it runs and drives brilliant. However at WOT the car judders around 3k. Ive tried new plugs, coolant temp sensor, cleaning the ignition amp plugs and a tank of super plus

The car is an agu, could it be something as simple as a fuel filter. I will get the car on vagcom later but Ive a feeling there will be no code recorded

Any one any ideas

Thanks
 

DaddyCC

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Maf failure would be common and show symptoms like this also. You could unplug it and go a quick drive to see if it runs any better.

But could be coilpack or air leak or dirty throttle body just as easily too. But try the maf first as its a simple easy one.
 

purplea4T

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Coil breaking down if you haven’t changed them, VAGCOM should record a misfire on whatever plug is starting to go.
 
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buster

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Thanks guys, il try vagcom and maf first. Car was perfect before I took it off the road :worried:
 

buster

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No codes on vagcom, I removed maf but it only boosts to 0.5 bar, the judder only happens at wot about 0.9 bar.

Would the coils let go on an agu, are they not reliable ?
 

purplea4T

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No codes on vagcom, I removed maf but it only boosts to 0.5 bar, the judder only happens at wot about 0.9 bar.

Would the coils let go on an agu, are they not reliable ?
They’re as reliable as any other electrical part! Pop the coils out and see if there’s any corrosion or damp lying about, especially with it laid up a while.
Does the judder clear or stay as the revs climb?
If you have access to VAGCOM, can you see the live readings from the MAF? Are these just 0.0 or do the vary with throttle input?
Check the 3 feeds into the boost solenoid as well.
 
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buster

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Yeah my mate has vagcom, I only scanned it but we can go out and do some logging. I'm hoping I might of found a potential culprit, the pcv isn't working and blowing at the oil cap. Il stick my catch tank on and see if that helps
 

purplea4T

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The pcv on these is pretty ****, hard to get at a lot of the pipes but it shouldn’t be building up that much pressure it’s blowing past the oil cap. They don’t tend to block, quite the opposite, the pipes fall apart and vent out that way.
 

buster

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I replaced the pcv pipes with a cheap eBay kit inc the check valve.I reckon the check valve could be stuck. When I had the catch can on it ran perfect,
 

wes

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As purple a4t said coil packs gave me this bother with my auq engine (180 cupra) back when i had 1
 

purplea4T

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I replaced the pcv pipes with a cheap eBay kit inc the check valve.I reckon the check valve could be stuck. When I had the catch can on it ran perfect,
Balls, pvc system wasn't the issue. Il get it back on vagcom Monday
I’ll have a check and see if we have any spare coils, even 1 and move it from cylinder to cylinder and see if the judder disappears.
 

buster

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That would be greatly appreciated bud, do you want to pm your details. Cheers
 
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