Hey, so a couple things have been going wrong with my car recently:

I have an 03 Lancer ES

The main problem I want to know about is why the engine revs up too around 3000rpm after around 15 to 20 min of driving and stays there. Normally my car sits around 1000 to 1500 i believe, but now after some driving time it climbs to 3000rpm and stays there no matter what I am doing, wether it be sitting at a light or driving...thanks

Thanks