After replacing the throttle body de-ice hose (thanks Steve), the truck idles high when warm. If you drive and come to a light, it will idle at 2000 rpm and usually, but not always, very slowly drops to 1200 rpm. If i tap the accelerator, it always drops to 800 rpm. Reading about the symptoms of a failing TPS, my symptoms dont seem to fit.

I took the codes and got an 11 (pass) engine off. Engine on gave me 52 (power steering) and 77 (brief wide open not sensed).

The truck starts and runs fine otherwise and works normally until the engine temp comes up. High RPM acts like a weak cruise control which is annoying if you just take your foot off the gas hoping to slow a little.

Any ideas? Engine is a 5.0 EFI. I sure appreciate any suggestions.

Chip

 

Don't pick words or part names out of code definitions. When you post a code, include the number and the COMPLETE definition, for each code.

The idle issue sounds like wear in the throttle shaft, either causing it to stick partially open, or allowing a vacuum leak. Don't disassemble anything, but slide the spring down enough to shoot a little clean motor oil on the throttle shaft.

(phone app link)


Also, check what happens if you pop the throttle cable end off the ball on the throttle lever, and then cycle the lever with the engine running - does it still hang & drift down to idle? Can you manually close the throttle & feel where the slop is?

 

Make sure the throttle is not being held open by the idle hard stop screw which should never be touched.Often the hardened steel throttle shaft will cause wear in the aluminum throttle body. You can pop off the throttle cable and make sure that the throttle shaft is free and returning to its proper position.If it is just binding and wear hasn't caused slop, it can be repaired but if too much wear has occured where there is slop allowing air in, you have to replace the throttle body.

 

Thank you both for your thoughts, I really appreciate the guidance. Diagnosing can sometimes be a challenge. ll hopefully have a chance to dig into it tomorrow.