Wanted to update one more time. In addition to the ecm being bad it was also out of time. Was advanced to around 16 degrees. Bought a timing light, set it at 4 degrees and it runs like new.
Just a heads up. Replaced the ecm with one from O'rieilly's and it fixed my shifting issues. Have all gears now. Thanks to all. Also my check engine light is gone for now. Going to do some data logging and see what's going on.
Have a new ecm on the way this afternoon. Going to drop the pan and check the internal harness and ohm out the solenoids too. I'll update shortly after. Thanks for the advice everyone.
Yes, the check engine light comes on as soon as you turn the ignition on and remains on. Disconnecting power dose not reset it either. Will come right back.
Thought of the input/output sensors. Did the swap and even left them unplugged and no change. Tps is new and tests good. I noticed when is disconnected the vss my speedometer was still functioning. Dose it not work of that sensor?
Hello all. I recently picked up a '92 Suburban 2500 7.4l for cheap. Has a newer crate engine with around 50k miles and 240k on the body which has almost not rust. I knew going in the engine had an issue, it would stall and idle funny unless you applied throttle until it warmed up. Figured it...