Mitsubishi Repair: tps- service engine soon, mitsubishi mirage, egr valve

Question
I have a 1999 Mitsubishi Mirage 1.5DE, automatic.  The service engine soon light went on. I took the car to the dealer because they just replaced my TPS. It was the second time that the TPS has been replaced. They then discovered that the diagnostic reading said TPS. He then checked the TPS and said that there was nothing wrong with the TPS. He said that he could not say what was causing the engine light to go on. The car also has a hesitation especially if you drive slowly or decrease ones speed. I added fuel cleaners to my gas and it still has the hesitation.Could you please give me some advice on how I can repair the engine light and the heistation.

Thanks
Mark

Answer
Mark,
There is a possibility that your car's computer is malfunctioning and throwing incorrect codes. Also, if the computer is at fault, it could cause other problems in your ignition system.  If you have an AutoZone in your area, they have a diagnostic code reader as well.  They can read your codes and determine if they see same error the dealership does.  The AutoZone code read is free, which is alway nice.

Other possible causes could be a bad EGR valve, sticky throttle plate, or even a worn accelerator cable.  It may be worth getting a second opinion so you can really pinpoint and fix this problem.
Good luck!