The SES light should come on everytime the ign. Is in the "on" position and go off after engine is started.
Could be a loose bulb connection in the SES light itself, or this coild be an intermittent problem.
The TPS (failure) will cause the ECM to set a default rich mixture, causing the rough idle you describe.
I would take to trusted garage or dealer and have ECM scanned with OBDI scanner in live data mode. Check TPS voltage signal. Should be <1V at idle and between 4.2 and 4.5 at WOT.
You may have gotten a bad TPS or the wiring to it is faulty, or the ECM may be the problem.
Sunday, February 28th, 2010 AT 9:06 AM