Mitsubishi Repair: Car revving up on its own, mitsubishi expo lrv, vacuum leak

Question
I have a 1994 MItsubishi Expo LRV, 1.8L. My problem is that when I start the car up and it's on Park, the engine seems to be revving itself up, as if someone is pressing on the acceleration and letting go. It's about one second revving up, one second normal, one second revving up, and so on. I've also noticed that sometimes, this happens when I am driving and the car accelerates on its own in the same pattern. If you could give me some suggestions or where to start, I would greatly appreciate it.

Answer
Alex: I would have the car coded, as the computer controls a lot of things in these little cars. But then you know don't you that Mitsubishi farmed out the building of their computers to another company which did not build very good ones. In some computers a piece will start to leak into the computer and with time it will kill off that computer. Now this shows up in many ways, one of them being revving. Still it could be that there is a weak or bad sensor too, so you need to take the car someplace and have the computer coded, it should kick out any problem with either the computer or the sensors through out your car's engine. Another thing to check would a vacuum leak but again a shop would have to help you with that too, as those are often than not hard to find. I hope this helps and God bless: Linda