My 2004 Chevy Venture has been in and out of the garage for 4 months trying to diagnosis a high idle. I have had the PCM replaced twice. I just keeping getting "there is nothing wrong" when obviously there is! I appreciate any suggests to fix this problem.

High idle can be a leaky plastic intake manifold,vacuum leak.Way to find it is with engine running at idle,spray brake cleaner or wd 40 everywhere,if the idle drops down momentarily,you have found it.I've seen this prob many times on many diff vehicles using plastic intake manifolds.