The surging and intermittent running sounds a lot like a failing fuel pump. How did the mobile mechanic check the fuel pump? just buy listening or did he check fuel pressure. I had a sum what similar problem turned out to be a fuel pump, you could hear it run but very low fuel pressure. Tank was full of junk and pump pickup screen partially blocked.

 

UPDATE!!

I admitted defeat, and had the truck towed to a local shop. Turns out that the chucklehead who had it before me, cut some wires that told the ECU how much fuel to send upon start. I don't know the particulars, but it starts now!

HOWEVER, it hesitates pretty bad below 40 mph. Added injection cleaner today. Slow driving is not an option. Another odd thing is that upon cold start today, it would sputter and idle would drop when I applied the brake to put it in drive. All I did was press the brake pedal. Strange to me. Anyone have an idea?

 

Either your brake booster is leaking, or you're running so lean the added air from the booster is putting it into a lean misfire condition.

Verify the accuracy of the ECT sensor.