I have a 1990 Coupe Quattro w/ 20V 5cyl that I'm starting to have issues with it starting. It starts every morning (without any real problems but idles very rough, on the verge of dying at times) when its cold. By the time it warms up it idles fine. The real problem I'm having is it seems to not want to start for awhile, if its hot, although the problem isnt consistent, sometimes it starts right up, other times I have to play with it, lately a lil starting fluid and cranking it over several times has done the trick. But has taken me up to half an hour to get her to fire up. Can someone give me some suggestions, is it the fuel pump, the fuel pressure regulator, fuel filter, could my aftermarket stereo be messing with the factory alarm? I read somewhere the crankshaft position sensor could be a possibilty, any ideas at all would be helpful, or if you've had the same problem I'd love to hear from you. Minus the starting issues, it's a great lil car and seems to run really good.
Any help at all is greatly appreciated.

Scott

 

Try cleaning the Idle air valve -- they begin to stick when the get old.

Do a search for IAV or IAC Sometimes it is called the Idle control valve.