my 2001 passat won't start. drove fine turned it off went to restart and it turns over but won't fire up.

in these older modal cars they have a bunch of crank case hoses and vacum lines that tend to break in thier older age and clog up. Find the crank case hose attached to the head and unplug it and check the line it will likely be full of sludge. replace the whole thing and it should correct the problem. And when i say all of it i mean all the valves and anything plastic attached to it. it costs close to 150$ but its worth it. this will be the likely cause of your idle issues. there is also a vacum line on the 2.8 engine that moves across the head under the plastic cover above the oil filller cap that tends to break and cause idle issues as well.

Thank you I'll try that. Is the Idle Air Control module a problem with these cars, do you know? Also on the intake there is a port to which no hose is there, it located on the front left side right there in front. I don't know what hose goes there but it's been off since I got the car. It's so frustrating.

if you are having problems finding wher ethings go do what i used to do. go to your local vw or audi dealer head to the parts desk and ask about that part of hte engine. they will have a sheet with all related parts in a diagram that they can print out for you for future referance. my audi repair manual was stuffed full of said diagrams to help me with repairs

as far as i know towards idle air control valves i am preaty sure they did out with them. by the way what engine is this a 1.8L or a 2.5 or a 3.0