What would make the idle go up @ 300 rpm's once engine is up to operating temp. It's an 86 F150 w/EFI ,dual tanks, 302 with110,000 miles. I have replaced temp sensor and the idle control motor, canister fuel filter on the frame and it still jumps up after it's warmed up also it won't start now with out a couple of shots of starter fluid? All worked well when I parked it mid winter . I'm open to any thoughts or suggestion. K.C.

 

My carbed 300 does the same. I start the day with a warmed up engine idling ar 600 rpm.
Later in the day I pull in the driveway and it's 800+.

 

first off, ether to start the engine is horrible on the engine. There will be some very heavy cylinder scarring from this in the long run, bes thting to do is figure out why it won't start on it's own and address that problem first.

Is the throttle body closing completely when you let off the accelerator? Maybe it need to be cleaned..

 

Could be the choke plate is not opening all the way. If its an electric choke, unplug it after its warmed up and see if it doesn't go back down. Check for blocked linkages, I had a vacc line runing through mine and caused a similar affect.

Could also be too much vacc at distributor? Also check the timing for the no start.