My brother just bought a 94 ZJ Orvis edition, 5.2 v8, when cruising around without hard acceleration it shifts fine in all gears, but if you hard accelerate up to 60 (3rd gear) it will not shift out of 3rd unless you accelerate up to 5,000 rpm. Any help or info would be very helpful, I avoid auto trans whenever possible, thanks.

 

Do a search on how to adjust the throttle pressure cable (kick down cable).