I have a 04 A6 S-Line. I was accelerating hard onto a hwy when the car jumped and heard a loud noise. My Check engine light come on. I immediately thought OH SH#@..... TURBOS. I dont know why. I slowed down and began to coast. I parked the car and turned it of. When I turned it on the ESP light came on. I took the car to my mechanic I have been using for awhile. He put the diagnostic thing on it and it said Mass Air Flow. I paid 350 and had it replaced. Two days later the bothe the ESP and Check engine light come back on. I am on the hwy and the car starts to sputter. I smell eggs and there is a brown smoke coming out. WTF. I seem to be spending money on this car like a DAMN CRACKHEAD!!!!!!!! Somebody shoot me and put me out of m y FREAKIN MISERY

 

The only thing I can think of that could cause the symptoms is a collapsed or damaged catalyst. The heavy acceleration may have put some unburned fuel in the catalyst that susequently exploded and dislodged the core. You might have a look at it. I can't explain the ESP light as a part of it though.

 

It has started to idle really rough. But not always. Sometimes it runs really good, but acceleration is very poor all the time.

 

Look at your turbo hoses. If one has cracked, the MAF will see all sorts of air going by it and it will richen the mixture, but air won't be reaching the cylinders and you will have an overly rich mixture, poor acceleration and brown smoke. Of course, this could take out your cat as well.

Good luck,

Bob

 

Thank You Sir, I will check that asap. I will also have the Cat checked as well. Will let you know what happens