I had this problem before and it was caused from overboosting. The car would then try to regulate boost pressure by controlling the TB. I would get misfires under boost, erratic boosting and the car would die sometimes due to the epc coming on. Check the vacuum lines going to the n75 and the WG. The line from the turbo housing to the n75 on mine had a hidden crack on it. This could also just be an n75 issue.

 

Still stuck on this problem. Changed the front o2 sensor but no improvement. Checked both o2 sensors and they seem to be working properly. If you drive the car with the front sensor disconnected, symptoms are similar but the car is even more undriveable.

Heading towards changing the ECU. Not much left to try. Any othe suggestions?

Thanks

 

The three problems that ive ever had with misfires are.

1. Water in my coil packs.
This was awful. i just dipped paper towels in and got all the water out after an hour.
2. My gap on my spark plugs was to wide.
I gaped it to .28 and bought new spark plugs.

3. My fuel octane.
I was being cheap onetime choosing to buy 89 octane gas.
Because of it, my engine starting to detonate early.

 

No, I have tried all these things. Always use 91 octane gas. I am still of the opinion its thew ECU or a faulty wire connection to the ECU from the MAF. Looking for the MAF to ECU wiring diagram if anyone knows where to find it?

 

OK, so the problem is finally fixed. My son has been driving the car with the MAF unplugged for a while. It gets really good mpg but is gutless under these conditions. Finally the car died on the road. It was obviously lack of fuel pressure. I had replaced the fuel pump less than a year ago, so I hadn't suspected it even though some of you thought this could be the problem. Well a new fuel pump and good pressure has solve the issue. The car can be boosted up to 17psig and it drives smoothly and pickup is good. Thanks to all for your suggestions. Is there a way with VAG-COM to read the fuel pressure? That might have helped right at the beginning.

 

Block 32 w/ key on engine off is fuel trim other than that 003 and 031 is fuel I think

 

ok. Thanks. I have the "free" version of the software which doesn't let me go above block 15 or so. I guess I should pony up the money and get the full version of VAG.COM.