Mitsubishi Repair: car wont go!!, timing belts, catalitic converter

Question
I have a 1990 gsx eclipse and since november the idle is VERY low.  It is a 5spd and as far as I know, until now the car has been really sound.  It started after a trip from columbus ohio to paduca kentucky.  It will idle at 600 rpm and sounds just pitiful.  We changed the plugs and wires and also changed the catalitic converter as well as the oxygen sensor.  I am so upset b/c I love my car and I dont want to take it to a mechanic that may tell me something that may not be true about my car.  Any information or help with trouble shooting would be greatly appreciated!!   Thank you very much!!!!

Answer
Tina,
The factory specification idle setting for your car should set at 750 RPMs (plus or minus 50 RPMs).  Your idle speed could be off for a number of reasons.  Your Idle Speed Control (ISC) motor may be having problems.  The ISC's job is to regulate the idle speed.  When the ISC goes bad, your idle will have problems.  Also, on top of the throttle body of your car is the Base Idle Setting Screw (BISS).  The BISS is used to adjust the amount of air that enters your intake when you don't have your foot on the gas peddle.  You can actually set your timing yourself.  The following web page give instructions if you ambitious enough to try it yourself:
http://www.vfaq.com/mods/BISS-1G.html

Another possible cause is that your timing belt needs to be replaced.  On a car such as the Eclipse, and especially the turbo model, that timing belt is critical for the engine.  If your really like the car, and it's been over 45,000 miles since your last timing belt change, get your timing belts changed ASAP.  If your timing belt were to snap, your engine would destroy itself, literally.  the bad part about having a timing belt replacment is the cost; usually around $500-$600.  If you do decide to get your belts changed, have the dealership do it.  They are the only ones that will do it correctly.

A low idle is nothing to worry too much about.  Having the plugs and wires changed is good preventative maintenance, and there is a good change you needed them changed anyway.  If you ever feel your mechanic is not being honest with you, don't feel bad about taking it to another mechanic for a second opinion.  
Good luck!