Mitsubishi Repair: 1992 Eclipse gsx, eclipse gsx, manual haynes

Question
Hi,

I have a 1992 Eclipse GSX 2.0L AWD manual tranny.  Lately the car has been idling high, around 1250 rpms and will fluctuate- go from 1250 to around 1500 rpms and then fall back down to 1250 rpms at idle.

Does this sound like the EGR valve or could it be something else?  Acceleration is fine, just the bouncing idle is driving me nuts.

Thanks

Answer
Will,
A boucing idle, or more commonly referred to as 'idle surge', is mostly due to a faulty Idle Speed Control (ISC) motor.  Also known as an Idle Air Control (IAC) motor.  This motor is responisble for keeping your idle at a constant RPM.  When the motor starts to go bad, it looses it's ability to maintain a steady idle, hence your bouncing RPMs.  The ISC is located under your throttle body.  If you have any type of service manual (Haynes, Chiltons, factory), they give a very easy procedure for testing it.  Or, have a mechanic test it for you.  That will probably reveal your problem.
Good luck!