Could not quite find this in archives-- but --
'99 2500 318 trans has overdrive.
The trans seems to think I'm trying to give it full throttle -- the shift points are way higher than normal. If I just release the pedal at the normal shift point, it will shift.

When I pull out onto the interstate, it really goes wild with the extra throttle. The overdrive seems to be working alright-- if I relax the pedal it shifts up to O/D and then will stay in O/D if I gently come back with the pedal. A little too much, though, and it's NASCAR time!

The engine has been having a real high idle (I was getting getting a OBDII code for "Target Idle not reached") that I attribute to a leaky plenum gasket -- gotta take off a day to fix that.

So I'm wondering if the ECM thinks I'm flooring it or is confused on the rpms and doesn't make the right shift points? Is the transmission electonically or computer controlled along with the engine?

Thanks in advance,
Lee

 

could be a bad TPS.

 

check your TV cable going down to the tranny... could be binding somewhere.