I have a 1999 audi a4 quattro. This all started when i pulled the fuse for the engine timing while the car was running. After this the car wouldnt start. I bypassed the ignition and hotwired the car...still nothing. I located a loose ground to the starter which was arching everytime i would start the car. Tightened that up and got her to start. But after starting the car it would only go to 1500 rpm and then jump back down. A code reader i bought told me the throttle position sensor was bad...audi dealership and 2 other mechanics told me the same thing. I replaced the throttle body and i am still getting the same results. PLEASE HELP

 

I fixed a car with the same issue. You need to re-calibrate the throttle position sensor. You will need the vag com software and cable. Instructions to do it are on the site.

 

sry not to be selfish but I hear that arch when I turn the ignition, do you mind mentioning where that loose ground was? hope everything works out man