Honda Repair: Engine noise, air control valve, honda prelude

Question
1991 honda prelude SI is having enine problems. The engine makes a revving up sound and then it revvs down and it does this continuously until the thermostat reads hot and then the sound goes away. What could be the problem?

Answer
It's really hard to tell without seeing the car. There are a lot of things that can cause this type of problem. A few things that I would suspect are the idle air control valve and the throttle body. These can both be cleaned and I would start with that. There is no way for me to pin point it much more than that though.