I have a 94 TA with 52,000 miles on it. Nothing other than 3" exhaust done to it, and the "Service Engine Soon" light randomly comes on. The engine temp gauge is reading fine, oil pressure looks good, and the voltage on the gauge looks good. It will just come on when I am driving down the road, and then go off sometimes, or stay on till I turn the car off. I havent seen it come on immediately at start up, and was wondering if anyone has any idea on what this may be (is it a typical problem?? maybe a sensor??) I dont seem to loose any performance, and dont think I could get it to repeat so that I could hook a scan tool up to it, because it just happens every once in awhile. It has only done it for about the last 1000 miles. Any help would be HIGHLY appreciated. Thanks

 

Trying to pinpoint what is causing the SES light to come on without proper tools is like trying to find a needle in a haystack. However, if the light came on, your computer has stored that info so you can retrieve it with a scan tool. I have a similar problem, cleaned the MAP sensor and the problem went away for awhile. Now I only see the SES about once a month or so. Good luck with finding out the culprit.