Thanks for the reply MBDOC, yes it is a CA. car and i checked the connector and attempted to pull codes, got nothing. I unpluged my coolant temp connector to force a code to retrieve and that worked out just fine. I was able to clear it as well. So no codes for the stumble and I'm still stumped too. I'm thinking I need to make sure my O2 sensor is working correctly even though it has about 20K miles on it. In your experience have you ever run across a problem like mine, car runs great in all conditions then out of the blue stumbles hard on itself recovers then runs great again and repeats awhile later?

__________________
1989 560sec with a few mods.