arren123

My 90 Civic Si has had NO problems starting/stalling during the cold weather in the east coast. During the 2 or 3 days we had nice weather 70+ degrees, the car has intermittent problems starting and stalling.

This is what happens.
From a cold engine, the car starts right up. Then then the revs will stay at 1000+ RPMs until the engine is warm OR it will immediately drop to 50 RPMS and act like its going to die. Sometimes it does die and then it won't start up until after a few tries or sometimes the revs return to normal. If I try to give it gas when its at 50 RPMs, the engine will die.

From a warm engine, the car may start and then drop to 50 RPMS and have the same problems mentioned above.

After the RPMS have settled, the engine will NOT stall during driving or idling.

I did notice last time when I was working on the car I let the engine idle for about 15 minutes or so. After it was warmed up, the engine would idle fine, then a couple minutes later it sounded like it was running at 50 RPMS again, struggle for a bit, and then go up to normal idling. It would repeat this process but would never stall.

What are some of the things I should check?