that could be a vac leak or bad/misadjusted tps.

 

Was it as hot as this one??????

 

Could be timing, do you have cats? Could easily be plugged cats, highly unlikely that's it's too rich, the extra gas would have a cooling effect on the header rather then a heated effect. I had this same issue with my Jeep, turned out that the exhaust had been crushed at the down pipe, it was backing things up.



I'd put my money on plugged exhaust or timing.

 

on top of plugged exhaust, tps. it could be the water thermosensor going bad..my car did the same thing and that was it