When I am on the highway at 65-75 mph and I floor it while in overdrive the car will shift into second past redline. Redline is at 5000 rpm in my car and sometimes it will downshift past 5500 rpm. I have had a TransGo Stage 1 shift kit, Corvette Servo, and .500" boost valve for 2 years on my 91 GTA without a problem until this year. My car has 119,000 km (74,000 miles on it and the tranny has never been rebuilt to my knowledge).

Last month I took the TB bolts off to replace the IAC housing and I left the cables attached to the throttle body. I also replaced the busted stock tranny mount with a Prothane one. I have adjusted the TV cable on a few occasions as per the instructions in the tech section but I still have the problem. Also, this does not happen everytime I floor it on the highway. Does anyone have any ideas on what could be the problem? Thanks.

 

mine did something like that and the problem was the tachometer started reading way off.

 

wierd.

mine did that when i got it but after a while it stopped, never figured it out for certain. only thing i ever messed with was the kickdown cable at the throttle was disconnected for a LOOOONG time, by accident, and then reattached and it was working fine.