Before you spend money getting scans, maybe a bit of old-fashioned trouble shooting would help. The 460 is notorious for high under-hood temperatures which fry the plug wires. New plug wires would be my first recommendation, along with a replacement distributor cap and rotor arm. Maybe new spark plugs would also help.
I've heard tales from friends at Ford that the exhaust manifolds can glow bright red (around 1800 degrees F) when climbing grades at low speeds on wide throttle openings.
I had an '85 Class C with that POS engine, with enough smog gear to run a cruise ship. It's best used as a boat anchor! I was never so happy to sell a vehicle as that one, despite taking a major bath. We could get temps on the passenger side of the insulated doghouse high enough to melt DW's tennis shoe soles.
I can't believe Ford got away with selling such a dangerous vehicle.