Actually, I was getting bad gas mileage when my dv went bad. It wasn't craked, it was just stuck open which robbed a lot of boost from going directly to the tb. So the maf was telling the ecu to send more fuel thinking that the engine was receiving more air. I now get about 3mpg more than I did before. But yeah try cleaning the maf with CRC maf cleaner to see if that helps. It could be a combination of issues.

 

Then it had to be completely cracked causing a boost leak, not just returning it to the turbo inlet hose. As air is returned less air needs to flow thru the maf, so your maf readings go down and the ECU decreases fuel based on that lower reading. Now if you have a boost leak to atmos, the maf readings stay up and the ecu thinks more air is getting to the engine then there really is. This will cause a non pre 2001 car to run rich. This is not the case with the 2001+ because the ecu uses the 02 sensor 100% of the time to adjust fueling to keep the AFR in check.

Think of it this way, if you have room for 2 cars to pass a spot and return 1 of those cars back to before that spot how many cars can you add to make 2 again? 1 and the maf sensor would read 1 car not 2 again.

 

I don't get what the hell happened then. I carefully inspected the old dv and there were no cracks at all. I remember hearing air escaping at wot and most of the time the car would then shut off. So something was causing a boost leak. When I replaced the dv, the sound of air escaping went away, I had a very noticeable power increase, and the car stopped shutting off.

 

Okay, so I jsut got my dv from a 97 s4. Went and put it in at work yesterday in about 10 min. Very easy install.

Anyway, the car is still doing the same thing. I got a check engine light from it about 2 days ago but it went away last night a few hours after the dv went in. It seems still when the boost gets to 11 or so the car bogs and the boost drops off. Just as in the video. On the freeway on the way home last night when It did it for like a good 3 seconds I could clearly see smoke coming from behind me. I noticed it because I was looking behind me when it happened. I couldnt tell what color it was but it seemed more like gas then oil.

Also, the new dv I put in had a much stonger spring just by testing them by hand. I also went out and pulled the battery for a good 20 min today to see if that would help and its still the exact same. I guess I can try making the engine light go again, im jsut afraid of it jerking so bad it hurts something trying to get there.

I mean, when I replaced the turbo it seemed to work fine, and then just gradually started jerking after about 2-3 days. Ill try getting maf cleaner and doing that as well. Just all of this happening like 3 days is making me curious as what could have gone bad in that time.

Im all ears for suggestions.