2001 GM Idle Speed Issue

My GM has 118K and has been serviced regularly. It began having electrical issues last year. After some driving problems, I wound up replacing all plugs, coils, and crank sensor. Then the temp gauge showed low temp. Replaced the thermostat and temp sensor. Warms very slowly according to the gauge now, but eventually gets to normal range. Now the car cranks a high rate of rpm and very slowly drops to close to normal. I have had the idle speed motor replaced and the throttle position sensor. Also, on three occasions the car has blown out a cloud of bluish smoke when it cranks because the engine revs so high. Where do I look now? No check engine light has come on.

Trade it in on a New FORD F150,than will be talking.

MCGIVER