Mitsubishi Repair: 95 mitsubishi galant rough idle whinning noise, vacuum leaks, mitsubishi galant

Question
I recently replaced the head gasket, timing belts, cleaned the EGR valve, replace distributor, checked sensors, etc. and cant figure out why the car won't run right. I know the timing is probably a little off, but that can't be all. The idle is rough, sometimes surges and possibly missfires. Plus there is this new high pitch whine that I can't seem to find where its coming from. The check engine light doesn't come on either and the car ran fine before my girlfriend overheated the motor. Any thoughts? Maybe Computer?

Answer
Paul: Why not have the car coded to rule out any problem with the computer or a sensor someplace. Only thing that I can think of that might cause a whine would be from a belt maybe or air zipping through something it shouldn't be. But that is about as much help as nothing, sorry. With some cars the check engine light never comes on, because the computer is bad but does not know it so it does not bother to kick that light on. Oh hey how about a vacuum leak, that could also cause that whine noise too. But you might have to get a shop to find that for you, sometimes those are right hard to find. If you have a vacuum leak, that would cause the car to idle rough, surges and missfires. Ok, from my trusty repair manual with ideas to check... spark plugs worn or not gapped properly, stark plugs fouled, stark plug wires damaged or shorted, rotor damaged or carbon tracked, vacuum leaks, incorrect ignition timing, uneven or low compression. Hope one these fixes your problem. God bless: Linda