Bought an 89 Civic Hatch today knowing that it had some problems but not sure what was wrong with. I'll give u a list of the symptoms.

1. At idle rpms Jump up and down
2. Moments after car has been started white smoke comes out the exhaust not a terrible amount but more that what condensation would cause
3. Car did not overheat after a 30 minute trip home and after sitting idleing in my drive way for 10 minutes after getting home
4. After getting home there was no more smoke coming out the exhaust at all. Idle was still bouncing though

My first thought because of the smoke was a headgasket, also i heard that sensors could cause the idle problems. I'm not sure at all whats goin on with the car hopefully someone can help me. The only has 120,000 miles on it, it is the 1.5 DPFI 4spd