Check Engine Light

Help...1991 Rodeo 100,000 + miles.
Runs strong, with all the new parts, hA HA. Has a stutter at 2.5-3ooo rpm. It is kinda intermittent, CEL comes on and goes out but leaves behind NO trouble code stored in the ECM. Truck has new exaughst, CAT, ignition, egr...PLUGS WIRES CAP ROTOR, PICKUP COIL.

O2 sensor should have been replaced at 100k. Check your owners manual it should be on the fix it list. Mine did the same at about 110k
94 3.2L

O 2 Sensor is newer, however, I had a plugged cat a while back maybe it is fried. I guess I'll pull it and check it out!

Shouldn't that send a code to the ECM that the ECM will remember and flash in a diagnostic mode? All I get is the code 12.

Thanks!

This is not fun......I had Pep Boys Run an engine diagnostic. They couldn't do it. Local Isuzu dealer backed up. P.B.'s said they couldn't get anything off of the computer. (I swapped computers last weekend...no change, computer was used.) Any suggestions.

I drove the truck today....at 2,000 rpm's and up it hessitates/surges/spits and doesn't get too much better. However, it hessitated so rough it came to life for about 2 minutes and went back to its old habit.

HELP I AM LOSING MY MIND, and wallet!