Diablosport Forums

I tuned a 05 GTO automatic and the car seems to be hitting the rev limiter before switching into the next gear. The A/F is good but inconsistant, the ECU will pop code for too rich every once in awhile but the A/F is between 12-13:1. On the dyno I cannot get the problem to happen but driving on the road 80mph it will hit the limitter and not shift. The rev limit is set to 6800 rpms and I raised it to 7200 rpms. I make one pull and it will go to almost the 6800rpms then a couple of runs later it will only pull 5800 rpms and hit the limiter again.

Sounds like the tranny may not be up to par.
The tunes do not have any control over any TCM functions, so it is up to the factory programming to command the shifts.
Does the car shift properly eith the stock tune in it?

Thanks