Mitsubishi Repair: Missing, throttle position sensor, high octane gas

Question
We have a 1995 Eclipse GS,Automatic Tranny. The car is missing pretty bad at an idle. It seems to run fine when not idling,but when we stop at a light , stop sign,etc..it begins missing. We just replaced the IAC because that was bad,new wires,plugs too..What could cause it to be missing at an idle?
                                    Jenni and Cody

Answer
Jenni and Cody,
If it's been more than 60,000 miles since you last got your timing belt and accessrpes replaced, they may be going bad.  Your other drive belts should also be inspected and replaced if they appear worn.  I'd highly recommend having that maintenance work performed.  Other maintenance items like air filter, fuel filter, and PCV valve should also be replaced if not done so within the past 2 years.  Have your throttle position sensor (TPS) checked, along with the EGR valve.  Have your battery and alternator load tested to be sure they are performing as they should.

Clogged fuel injectors can also cause this problem, so during your next fill-up, add a bottle of fuel injector cleaner with a tank full of high octane gas.  
Good luck!