This is my first post so just hear me out and if I leave out any important information just let me know. We are talking about a 2001 Audi tt quattro I purchased a month ago. I got a really good price so I took it problem is the car has a few miles. It ran great but had a little noise (like a belt gone bad noise) I didn't care and kept on driving. Two months after at a light the car just died, it wouldn't start no matter what I did and was giving me a code (cam sensor). After hours of checking things we realized that tahe crankshaft gear was slipping on the timing belt. Guess they never replaced it and it was missing 4 or 5 consecutive ribs. I thought I had to replace the head and all that. I started by replacing the belt, water pump and serviced the belt tensioner. 90 dollars later and a couple of days worth of work I was back on the road. Didn't have a single problem till yesterday. I was driving and it felt like loosing power and it would go back to normal and loose it again. Almost like running on 3 pistons or running on fumes. I thought the spark plug was bad so I checked them and they are good, look like they are burning great (replaced when purchased the car: split fire) so the onlything left to blame is the coil or the injector. Now the worse part it is not a constant problem so is hard to locate. I switched the coil from piston four to three but the problem is still on four. The only codes are P0304, P1124 and P0128 or P1128 not sure about the last one. Can anyone help with this little bug? On top of that I don't even have the repair manual/CD is way too expensive. Still looking for a cheaper alternative.

 

P0304 cylinder 4 misfire
P0124 throttle position ( TP )sensor A /accelerator pedal position (APP) sensor A - circuit intermittent
P1124 ?????
P1128 long term fuel trim, entire speed/load range, bank 1 - system too lean - problem is fuel pressure/pump, injector(s), intake/exhaust leak, air system, hose leak.

check wiring and connection to throttle position sensor/cam sensor/ air/vacuum leaks/exhaust leak, squirt some water on injector No4 to see if its drawing are through the seal

 

No4 to see if its drawing air through the seal

 

Erase the codes and see if it drives any better. If it drives better for awhile and then starts running like crap again, replace the mass airflow meter.

 

id switch injectors then check compression and do a leak down on cyl 4. a maf isnt going to cause 1 cyl to misfire.