Hello Ford friends, I'm new here, so bear with me!

Pulled the trigger and bought my first Ford, an F-250 XLT Lariat EFI 460. I've only ever owned Jeeps, Chevys, and Hondas, so I'm in newish territory.

Bought the truck on the 3rd, test drove it and everything went fine (as always happens). Guy who sold it to me said it had sat for a while, but he had put a few gallons into the front tank and the thing started right up and ran fine and we had a good test drive. He even gave me 50 bucks out of the $2500 sale price to fill it up (fuel pump floaty dongler is obviously loose so the fuel gauge is wacky) I drove it home after purchase and it stalled once, but I figured everything needs a good cleaning/replacement (251k mile vehicle). Predictably, I got (a little) excited and decided to drive it to work the next day, hoping to maybe blow the minor cobwebs out with the ol' Italian tune-up....I made it to work, but only after I stalled every 1-2 miles and couldn't make it up any kind of hill ( gonna use one of my free AAA tows to get it out of Aurora, CO ASAP if I can't limp/thunder back home tomorrow). The best I could do was to verrry gingerly feather down on the accelerator, truck seemed to not totally hate that between stalling. It would start right back up though. I got gungho and had only checked fluids (they were old but not burnt/terrible) before my first trek in my awesome big a** 8k lb truck.

I have a fuel filter and fuel pressure regulator on order to pick up and install tomorrow (fuel is the first gremlin right?), and maybe some additive to clean the injectors. My most hopeful guess, is that when i flipped the switch with faded lettering to the left of the steering wheel a la "WHAT'S THIS FUNNY SWITCH DO??" driving home from the sale, I sucked some really nasty fuel from the second tank into the shared filter/external pump (which could both be full of varnish anyways yes?). What I noticed while doing laps around the work warehouse on my lunch breaks (probably looking like an idiot) after cleaning this and that, was a heavy fuel smell. Deposits in the throttle body department and the XTREME side-by-side dual exhaustilators (haven't actually even checked if they Y or they're true duals) definitely smelled like fuel. I have a fuel pressure gauge, but of course, the shrader valve on my fuel rail is smaller so I haven't check that yet. Might drop into the Home Depot tomorrow to see if that have a brass reducer (probably not).

Anyhow, I've seen this and that about the IAC, TPS, and the MAP acting funny. Those aren't new problems to me. I just feel like something simple is getting too hot and quitting. I'm ok with this thing becoming parking lot art until I have the scratch to get really serious and dig in when it's not 98 degrees outside, but it'd be nice to get a few 10K miles outta the engine yet with minimal easy parts replacement; it's been a very well upkept vehicle (previous owners wrote a novel with upkeep etc. that's in the console). I've never been so lightning-struck by a vehicle until now...the only weight reduction is what you see (may have to scrape off the ancient Bears ( or Cubs???) sticker):