What would cause engine to rev high while driving?

[PrimerPLus]

So was looking around and I think I found a decent deal on a 98 eclipse gsx that comes with a 97 eclipse rs for $4000. The guy said that the gsx starts to rev high after driving it for a while. He said the mechanics said it could be the thermostat. Any other ideas?

Also any other things I should look at while checking it out?

1998 AWD & 1997 FWD Mitsubishi Eclipse

 

[92AWDHX40]

I would pass and find something else thats just me seems like a headache in the making.

 

[brian102]

Rev high while in neutral? I bought one that did same thing. Guy said his mechanic thought it was idle air control valve. Ended up being a vacuum leak. Could be simple to fix could be costly.

 

[PrimerPLus]

Rev high while in neutral? I bought one that did same thing. Guy said his mechanic thought it was idle air control valve. Ended up being a vacuum leak. Could be simple to fix could be costly.

Well he said it starts to rev after its but running / driving for a while.

Is this car worth it?

getting it for 2k each and i can sale the rs later.

The only other options right now are these

http://fairbanks.craigslist.org/cto/2505866075.html

or http://anchorage.craigslist.org/cto/2557187546.html this is fwd not awd

but if the first one is not going to be a pain i think its the better deal.

 

[Dustin269]

mine used to do this and it was the throttle cable sticking after it warmed up

 

[Nasty Dream]

It's revving high, or idling high?

If idling high, especially if it revvs up and down by itself continuously, I would be sure it's the idle speed controller (ISC). Sometimes called the idle speed servo.

...can give more information if you need.

 

[whtgst]

mine used to do this and it was the throttle cable sticking after it warmed up

same here, when it did it last i just loosend the 2 10mm bolts holding it down and the idle came back down. then pulled the slack out and retightened it. been good ever since.