I just recently had an engine swap with a new engine and also installed a fidanza 8lb lightweight flywheel and a new clutch. My problem is that the idle is never consistent. I brough it back to the garage where I had the swap and they couldnt diagnose any problems which is a bunch of crap. Sometimes the idle is at 1500rpm and other times its at 500rpm which is too low. Then I tend to be hard on my car once and awhile and when I come to a stop either at a traffic light or somewhere else the idle just goes crazy. Since this isnt my original engine Im not really used to how it reacts to this type of things. Do you think a lighweight flywheel might have something to do with this because of the rotating mass and inertia of the flywheel can affect the idle. What do you guys think?

 

anyone?

 

check or replace you IAC

I had the same issue when I swapped and I found that the rubber ring gasket got twisted and was not sealing right.

I got off cheap. Most have to replace it.

Look at air lines to it for cracks, check clamps, make sure the 2x 12mm bolts are tight, check rubber ring gasket.

Good luck