I currently run a '91 Mitusbishi Eclipse GS at the local track. When I return into the pits after the 10 lap feature race, I notice that the car is jumping from 1200 to 1500 rpms. Why is this and what can I do to quickly fix it. Please help.

 

that's not a very big jump so it may just be from stress on the car. but a few things can make ur idle jump. throttle positioning sensor (tps), timing belt, blown head gasket... there are a few things.

 

Its an N/A 4g63? VERY likely the TPS

 

when my head gasket blew mine was fluxuating but a lot more. TPS would be my first guess and check also.