hey all, i have a 1990 talon tsi. i just rebuilt the engine and its idling a little rough like it goes up and down like 400 rpmwhen it idles, any ideas on what it could be?

i would suggest you go to garage and check the pistons, but i suspect its lacking tune up.

how about we start simple and check for vacuum leaks and looking at your spark plugs and make sure your wires are routed right...thats the logical thing to do.

+1 vacuum leak would be the first thing I checked on the car