i think its my transmission.

[Unit 5302]

Originally posted by Mr 5 0:
Help us out with more info;
If an AOD, the fifth gear band may be going out.

Damn those 5th gear bands in that AOD!!! I bet those extra gears that were errantly installed in that tranny cause more failures than everything else combined.

Sorry, I couldn't resist. If you have a 5th gear, you've got a T-5, and the problems you are bringing up here are not transmission related.

The wrong sized tire can make quite a little impact, so that could certainly be causing part of the speed issue. More likely it's just a vacuum leak in the cruise control system. Mr 5.0 is right though, we could use a little more information.