Also keep in mind that with these trucks you are interviewing the previous owner for their maintenance habits as much as you are examining the vehicle.
Forscan Lite + a good blue tooth adapter is the cheapest/most effective way to dig into these truck’s brains.
FORScan Lite application was developed specially for a computer diagnostics of Ford, Mazda, Lincoln and Mercury vehicles. Supported adapters: - OBDLink MX+ (recommended) - vLinker FD BLE (recommended) - other ELM327-compatible WiFi or BLE adapter (not recommended). Attention: this application...
now to the mechanical
1) Check for oil leaks
2) if it’s a long crank, is it turning slow or fast when you crank it? Hard to tell if you haven’t been around these trucks much, but kinda have to determine that. Might throw some jumper cables on it to see if some extra amperage helps it go faster. Might be all you need is to clean the terminals, or it may need new batteries (group 65 batteries ain’t cheap)
3) if you determine the cranking is adequate, look at the ICP and IPR duty cycle on forscan. If they come up to pressure quickly while the truck is cranking quickly then you’re set. If not then see number 1. Look deep into the truck’s valley.
If it’s had wiring worked on and it doesn’t look clean and well done, I’d probably run away.
Has the trans been worked on? At 340k it could be on its last legs if it’s the OEM unit. If it’s been rebuilt, how has the new unit been maintained?
These trucks are great, and they can be super reliable while still making good power. They’re not gonna be a crazy 2000 hp race truck or whatever but they can make enough power to pull anything you want, and still put a smile on your face while doing it. Listen to the people here (not me, I’m an idiot), they know their stuff.