I hope someone can help me here? I have a 94 z28. It’s all stock and original. Trans has never been touched. The car has about 130,000 miles on it. Car has been very well maintained. There are no codes logged.
The problem I have is when I am cruising at about 35mph the rpm is at about 1200rpm and I go to wide open throttle the car seems to be stuck in 4th o/d lockup. I hear the engine make more noise but the car won’t accelerate. Usually if I back off and try again it works fine.
This does not happen all the time. It scared the hell out of me last week when I tried to pass someone in a canyon! It seems to happen most often when going uphill
I have replaced all the internal trans switches and solenoids. I have replaced the Throttle switch. No change.
I would appreciate advice.
Thanks,
Walter

 

torque converter lock-up solenoid maybe??? not sure if you did that one yet but if not, it's a place to look.

maybe the car is actually shifting (hence the "more noise from the engine" thing) but the converter is staying locked, bogging the car.

good luck.

 

Some times when you kick it down it'll only drop down to 3rd gear on the first attempt but if you let up and kick it again it'll go down to second gear. This is controlled by the PCM programming. It depends on how fast you're going.