My car upshifts all the way into 4th gear well before 30 mph and throttle opening has no effect. Won't downshift even at low speeds. Could this be caused be something other than the computer controls? I have a Predator but it has no effect.

 

Anyone?

 

does it do it with the predator tune off?

 

yes. It's as if the computer is not controlling it and it's shifting based on what the trans would do with minimal throttle.

 

Throttle position sensor? You can check the voltage with a scnner or a volt meter. WOT needs to be around 4.6v

 

Checked that out and it's ok.

 

Could something that controls the tranny via the computer not be plugged in?

 

How did you check it?

This definately sounds to me like a TPS issue. Watch the values with a scanner. If the TPS is registering properly then something in the programming is screwed up. I have seen cars do this right after installing a bigger throttle-body too due t oletting in more air at lower TPS and making more power...