Briefly...
72000 miles- Check engine light comes on and goes out after three days.76700 miles- check engine light comes on - diagnosed as bad catalytic converter. Replaced under warranty.
82,000 miles- Check engine light comes on and goes out after three days.87,000 miles- Engine has full tuneup, found out that the light code was for lean engine, but it still runs rough. Fuel filter changed, but no help (pressure was good though). Dealer does "top engine clean" but this does not help. Checks MAF and TEMP sensors which are good. Winds up changing bad Oxygen sensor (catalyst monitoring) and Evaporative pressure solenoid (vent soleniod was stuck open). Car seemed to run better, but next day check engine light came back on and car seems to be running rougher, but that could be my imagination. Any other ideas as to what could be wrong? Dealer is stumped!!!!!