the codes read for 'free', that's hard to beat. Find out what they are and let's us know.

Yes, the CEL can go on and off: it goes off if the fault has not occured for a certain number of 'trips'. Trips are not just running the car but close.

Without finding the codes, it tough to t/s. Actually WITH some codes, it's still tough but that's the best place to start.

Could be alot of things from an O2 sensor, MAF sensor, fuel trim and/or the dreaded disintigrating 'wiring' harness.

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Regards . . . . JimF
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'94 S500 Cpe

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