My car (02 Jetta 1.8t AWP) has been suffering from cold start and normal idle issues. I figured it was a simple vacuum leak issue, so I've been tracing vacuum lines for a while.
To rule out coils, I got them all replaced under warranty and even did the overlay harness.
The car has been to the dealer a few times and they have given the diagnosis of the vacuum pump. They said at one time they replaced a 20 amp fuse, the other time they simply said the vacuum pump needed to be replaced.
Yesterday I decided to check out the vacuum pump. I located it under the car and the line from it runs from the electric pump to the brake booster. It didn't, however, ever turn on. I never felt the pump kick in and my idle was terrible.
I'll probably continue looking at the lines, especially the one from the brake booster to said pump. Any input?