My 95 Cutlass has a strange idle problem. The car has the 3.4 liter V6 and a little over 80,000 miles. Here's what happens.
Sometimes, not always, when I start the car the engine runs up to about 2000 rpm. If I wait before I put the car in gear it will eventually settle down to around 1000 rpm. Today when I started it, it ran up to about 3000 and then dropeed to 500 then back up to 3000 then back down. It did this until it stalled.
Once I start moving the following happens. Lets say I'm at a stop light and the idle speed is at about 1000. As soon as I tap the gas, the engine speed goes up high enough that I can go about 35 without even touching the gas with my foot.
When I stop and put the car in park the rpm usually goes up as well.
This problem never really goes away but does seem to get better once the car warms up and I think its worse in cold weather but I'm not sure.
I did repair a couple of vacuum leaks a few months ago but this didn't seem to have any effect other than fixing a vent control problem