Hi Clayson,
No worries- I hope you enjoy it!

Feel free to interrupt with any ideas on the issue at hand!

 

Yeahh sorry about that. The ATW is the bastard child of the 1.8Ts. 058 block, small port head, no ICM (as I just learned), DBW, but narrowband tuning without a MAP sensor. The stepping stone from the AEB to the AWM.

It's not uncommon to have the car idle fine but misfire under heavy load. Same thing happened to me when I lost a coil. Car would drive fine unless I stepped on it.

I would still replace the plugs if you haven't already. I'd also start examining the coil pack harness for cracks or faults. Again, the randomness makes me think it is something further up the line. Double check the coil pack common ground.

Good.

 

Changed the coils and plugs (gapped to .028 since I plan on flashing the car when this issue is resolved) and replaced a vacuum line that went from (under the intake manifold to some T fitting below the Turbo? very small) and cleaned the MAF.

Drove the car a couple miles on the highway extra hard, no issues (besides no boost but car felt great)

Turned the car off, went inside to take a shower then drove to the store- not misfiring but riding like crap again.

Any ideas?

 

Clean the MAF.. check for any leaks in the air intake system. You can check for leaks in the vacuum lines. Maybe a PCV leak?

I know these suggestions are unlikely but your best bet is to take a few things apart and put them back together.

You would be surprised how many lines are loose or cracked or brittle or clogged for whatever reason.

Then again... if you have checked all of that.. it is once again highly unlikely but possible that your cam tensioner is failing. I don't know if failing valve stem seals could cause these type of symptoms.

Could engine sludge cause slight misfires? Probably. I know that seafoaming the hell out of our car's can cause misfires too.

Just ideas.

 

Thanks Kamil, I'll check it out!