GM-GMC: High Reving, olds cutlass supreme, intake manifold gasket

Question
Hi, I have a 96 olds cutlass supreme with a 3.1L engine. Two weeks ago I had it in for a major tuneup,,,plugs, wires, fuel filter..etc. At the same time they replaced the intake manifold gasket (3rd time since I owned the car). Now two weeks later my car revs very high on a cold start. ( I live in Ontario Canada...cold winters) It stays that way til it somewhat warms up and I turn it off and back on again. Today it did it again and it just drives itself down the road due to the high reving. The rpms were in the 3 range and I couldn't go any faster than 30 kms/hr. I took the car home and parked it. Any ideas? Thanks in advance

Answer
There are a few things that could cause that type of problem.  One is a vacuum leak.  Listen around the upper intake and around any hoses or lines for a whistling or hissing noise.  It will allow unmetered air into the engine and cause the idle to rise.  But to hit 3000 rpm it would have to be a pretty large vac. leak.  More likely you have a problem with your idle air control valve, or IAC.  I would return to the garage that performed the repairs and explain to them what your concern is, and it is a concern, a car that will drive itself down the road isn't very safe.  Also there is no reason to have replaced the gaskets more than once.  The original design gasket was a poor design and it has been updated.  If the proper gaskets were installed properly they should last nearly the life of the car.  I have over 400,000kms on my 3.1 and I replaced the gaskets once at 45,000km, 6years ago.  No leaks no problems since.
Hope this helps.  If you don't get any satisfaction from the shop that did the original repairs.  Let me know and I will try to help you more.
Hope this helps.