I have a Ford 801 diesel tractor that I use to mow the pasture and perform some box blading. Lately, and not every time, when I start the tractor with the throttle in a normal starting position, the tractor will suddenly go into an extremely high idle. If I adjust the throttle, the idle will go so low it will stall if I do not adjust the throttle again. I engage the pto and begin mowing and most of the time it will suddenly return to the proper idle and I can mow as normal. Other times I have to constantly move the throttle up and down until it returns to the regular idle. Anyone else have a similar issue and what it may entail to repair? Thanks for any replies!