Del does not follow his own advice, AKA Cummins Whale

The heater is "crazy" I'm guessing vacuum pump problems.
No vacuum controls, all electrical. Likely a mode/temp door actuator, sold a ton of them over the years.
I already found some advice on the www that you should watch the lift pump pressure to prevent failures on the injection pump
Be real careful of the lift pump going bad! You won't even know it went until injector pump craps out on you.
There was a TSB out there once upon a time that moves the lift pump to the tank like a normal fuel pump. If you have that set up, you should be good.
Have fun with it. I've kicked myself in the *** several times since last summer. I let a damn nice 07 4X4 4dr w/98K get past me. I should of just ponied up and bought it. I haven't seen one that nice since.