05 2500 HD 5.7 Hemi. My cruise control will allow the truck speed to drop by up to 8 miles an hour before returning to the preset speed. No codes and everything else works (heat controls etc.) any suggestions?

 

Based on my experience you may just have to live with it...I don't think mine has ever dropped that far, but once it gets far enough it's violent (it floors itself) getting back up to speed.

 

Terrific. Mine is definitely violent. I have a plug change on the schedule so maybe some improved performance will help.

 

Funny thing is, my cars aren't like that. I hit resume even 20+mph down from set speed and they just smoothly (no downshifting or full throttle) make their way back to it. Might be a CAN bus vs PCI bus thing.

 

My Avenger has no issues with it either.

 

CAN bus vehicle lol

 

hmm, Quality Control issue?

 

Definitely a NO to that. This is normal for a truck. A truck is much heavier than cars etc mentioned. More inertia to speed up and to slow down. The CC program also tries to adjust the speed gradually without jump gears around. It will hold in same gear as long as it can to avoid that. There can be a dead band in the engine power at the rpm at the speed you are setting the CC at. Find a sweet spot. Set it 5 mph higher or 5 mph lower.

 

Face, nope wrong answer. I've driven Super Duty's, Chevy 3500's gas, diesel and even heavy trucks. Even my father in law's 99 Ram 4x4 5.9 magnum is rock steady at the speed you set it. This is the only one that the cruise varies by up to 6 mph and then downshifts and tries to catch up. The sweet spot is my foot and brain keeping it steady not the cruise. Totally empty on the freeway last weekend it still did it. Makes no effort to adjust speed until the drop is at least 5 mph. If all of the gen 3+ trucks do that, it's a poorly written algorithm that should be revised. I won't get started on factory firmware updates. Not much logic being used in that department. Set it 5mph higher or 5mph lower. nope sorry. I should be able to set it at 75 and the truck will stay 75. not 60-75 every time there's an incline. That's why CC exists, to maintain speed.