Well, as the title says I may have a problem. I use cruise all the time and never really noticed this problem until recently. I never really like my engine revving past 4500 RPM max so when it does for no reason I get worried. Well lately on hills in cruise doing about 110 KMpH It will down shift and rev at 2500 and feel good and keep speed then all of a sudden down shift yet again and rev at 4500-5000 RPM.

Well I let it do its thing tonight thinking maybe it will hunt some more for 3rd. I got to the top of the hill and flattened out but still no up shift. 110 KMpH on flat ground in 2nd at 5000 RPM. I have to tap the brake/cancel cruise for it to down shift.

Can someone give me some guidance?

 

I know that I'm not the only one now. Anyone have any suggestions?

 

This is a very odd problem. The cruise control doesn't (or rather shouldn't) directly alter the transmission operation. The cruise control module simply pulls on a secondary throttle cable to maintain speed, mimicking your foot.

When the shift lever is in OD, transmission downshifts and upshifts occur mostly based on the speed and calculated engine load. Engine load changes based on throttle position amongst other sensor inputs.

Maybe there are some wires crossed and the PCM is thinking that the throttle position is sufficiently high enough (in terms of percentage) to warrant the downshift(s).