series 60 wont return to idle, intermittent,
My 1999 series 60 will sometimes not return to an idle. You will be shifting up through the gears or trying to downshift. Push in the clutch, let off the fuel pedal and the RPMs will only drop to 1200-1300. It doesn't do it all the time just every now and then , but seems to be getting worse. It will sometimes do it when the truck is just idling. It will just rev up to 1300RPMs and sometimes rev back down to idle and keep doing this. Sometimes the engine stays revved up and other times it slowly goes back down to idle. It does sometimes trigger the check engine light when it happens while driving and hopefully I'll have the code for you guys tomorrow. Engine is in a 2000 freightliner century. Does anyone think its the throttle position sensor? I have no experience with this at all never had a engine do this before. Any help would be appreciated.
Is this a good question?