97 Astro gone nuts

[nxk2000]

I have a 97 Astro that has a shutter/miss. It is most noticeable when driving down the highway when the converter is locked up. No check engine light. What I have found odd about this problem is just before it happens the system will bounce from closed loop to open for a second then back. I have recorded the data but found nothing consistent to narrow it down. I had the MAF sensor go way out of range just before it happened but it only happend once. Another time the readings switched between the coolant temp and air intake temp sensors then back again. Not really sure what step to take next. Any suggestions would be appreciative.

[94&92Astro]

Originally Posted by nxk2000

I have a 97 Astro that has a shutter/miss. It is most noticeable when driving down the highway when the converter is locked up. No check engine light. What I have found odd about this problem is just before it happens the system will bounce from closed loop to open for a second then back. I have recorded the data but found nothing consistent to narrow it down. I had the MAF sensor go way out of range just before it happened but it only happend once. Another time the readings switched between the coolant temp and air intake temp sensors then back again. Not really sure what step to take next. Any suggestions would be appreciative.

WoW- I would start with plugs and plug wires and then check with the engineering dept after I eliminated the simple things...