Thanks for the welcome!  I am wondering if anyone  has had the problem I'm experiencing with my 94 ZR-1 with 22K on the clock.  Periodically I will get a Service Engine Soon lite  after having driven  at highway speeds,or above, for around an hour or so. All guages read normal, engine performance unchanged. Should I stop  and restart, light goes out and rarely  recurs during that trip.  Driving around town, regardless of amount of time driving does not get the light. I'm going to assume it's related to the Corsa Performance exhaust, although Corsa states that their exhaust should not cause this. A check of codes, when I've had the chance, is never consistent. Ideas anyone?  Thanks, Gary M.