Hi Folks, new guy here. Hope to be here a while I just bought an '85 F250 Explorer with the 460, and I'm having a series of problems that I'm pretty sure are all related. I'm not at all experienced with these motors (I mostly know small-engine imports from the 90's and early 00's), so I think I need some help. I'm seeing three symptoms:

1. It can be very difficult to start. I will crank it for 3-5 15-second stints, sometimes pumping the gas, sometimes not (just trying everything I can think of), and it will eventually start. But once it does start...
2. It runs very rough. It sounds like it's about to die (very low idle speed), and if I give it any gas, it actually will die. Once it has been running for a couple minutes, I can very slowly give it just a little gas and it will gradually speed up to what sounds more like a reasonable idle speed. After about 10 minutes, it sounds fine, like it doesn't have a problem at all. Although, it seems not to modulate it's idle speed on it's own. Without throttle input, it would never alter from it's initial low idle.
3. Once it is running and warm, it acts exactly as I would hope, with one minor issue: If I'm stopped or nearly stopped and I hit the gas too abruptly, the engine will hesitate. The harder I stab the gas, the worse the hesitation, killing the engine if I just jam it. If I give it 1/8 throttle for a second first, waiting until I hear the engine respond briefly, I can hit the gas as hard as I want after that, and it responds perfectly.

Based on what I've read in these forums tonight, I think I need to check the choke tomorrow. Am I on the right track? Tips? Insults?

 

Check the choke for proper operation and also check your accelerator pump.