Last week, my car died when I was driving it, it started studdering, and I had no acceleration. I managed to get it into a parking lot and get a code reader. Car is a 2000 A4 1.8tq 5 speed, giac chip, exhaust/dv.

I scanned the codes with a code reader and found:

16839 - EVAP Emission Contr.Sys.(Gross Leak) Leak Detected (had this one since I got the car)
17743 - Engine Torque Monitoring 2 Control Limint Exceeded
17965 - Charge Pressure Contr. Positive Deviation

So I brought the car to the shop nearby to take a look at it, and they found the DV came apart. So they cleaned it and put it back in. I drove around after for 30 minutes or so. It feels great, holds boost for the most part, but there are still three issues:

-When I cold-start it, the RPM's just surge from ~800-2000, and the boost gauge surges up to about 0psi. When it revs up a bit I hear a sort of whooshing noise but I cannot isolate it in the engine bay. I let it do this for like 5 seconds, then turn it off, then on again. The third time (always) I fire it up, it idles at 800 smoothly? WTF

-When I'm driving, it doesn't do it all the time but sometimes if I press down on the gas, the car shudders a little bit, then it goes away after like a second.

-The worst thing probably, is that when I'm cruising let's say going 30 in 3rd gear ~2200RPMs, and I pop it in neutral, the RPM's drop ALL THE WAY TO 0 and the car dies/locks up the steering column. column.

I still need to do a boost leak test (haven't had time) even though the garage I brought it to for the DV said that they checked and it was fine, I want to make sure. I've been doing lots of research and the things I have read could be the culprit are:

-bad N75 valve - is there any way to test this out by itself?
-Some other sort of boost leak
-ECU problems. Mechanic told me a buddy of his had a '00 on a GIAC tune and it had the same issues, and they never found anything else causing it. I have read similar stories on AW/Audizine about the 2000's on GIAC. Does anybody have experience with this specifically? If it is indeed the tune, can GIAC reflash my ecu for me?

Thanks a lot guys, any info would be greatly appreciated.

 

nvr seen the last 2 codes b4. the first one is a vacuum leak, you should def fix that asap. pm auditech79, he'll know what to do

 

The tq limit code is what caused the car to die. When the ecu senses that the tq limit has been hit it will cut the controls of the thottle causing the car to just coast to a stop. This could tends to be thrown at low rpm and part throttle.

The 3rd code was caused by the broken DV, ecu sensed that the pressure at the map sensor in the IC was reading lower boost then what the ecu is requesting. This will also happen when a IC hose pops off. If the leak is large enough the car will not idle since all of the air will be coming in at that spot causing the MAF reading to drop so low the engine wont be getting any fuel.