2000 GTP original motor spun bearing, replaced with a "recycled" motor. That motor was about to spin bearing and showed 12-15 hg vac at idle.
Got another "recycled" motor just put it in and plugged in. Started and ran fine, after getting on the hwy it started to have a fit bucking, stumbling, and wouldn't stay running even in neutral at traffic lights.
I checked/cleaned every ground(under hood), cleaned the positive connections, took apart and cleaned ICM and coils.- Also cleaned up the bracket on which the coil pack sits. Replaced battery bolts, both the alt, bat, and starter were checked and tested fine. I started it up and ran/idled perfect showing 17-20Hg vacuum. I let it sit idling while I picked up tools(5 min) drove away and within a mile it starts having a fit again which got worse as motor got warm. Once cooled down I switched out ICM and coils and barely started ran rough and showed about 12-15Hg of vac again!!!
No SES lights but bat and oil.
Oil level is fine.
All vac lines are perfect.
I am lost!! Any ideas?? I have searched the forum and haven't found the same symptoms has I have... Feel free to PM me.