hello, i have a 1994 2.8V6 coupe quattro, with a bit of an annoying problem.

The car has an irregular tickover which sometimes causes it to stall and also it feels like it is strugling under heavy acceleration, especially in 2nd and 3rd, when going above 4k revs.

any ideas what it is?

 

I believe my 1990 100Q has a similar problem. When it's cold out, like it is now in Ohio, I hear a "tick" coming from the engine that increases with RPMs. Also, it feels hesitant, even somewhat 'jumpy' if I try to accelerate too quickly.