Truck starts fine but immediately needs gas pressed otherwise it will stall the moment I let off gas

Not sure what is (un)related. But a few things happened within a month's time:

1) Parasitic energy draw from the interior lights/radio fuse was killing my battery. Removed the fuse and solved the problem for one month and another parasitic draw happened and killed my battery.

2) Jump starting requires gas pedal depressed to keep it running indefinitely. Engine does not sputter/miss/backfire/idle hard (and never had any of this symptoms prior). Engine dies so fast that shifting into a gear is not possible.

Things done/noticed:
1) Throttle body seemed not terribly dirty to start with, but was cleaned a bit.
2) When the vehicle is "on" (not running), two wiring harnesses were tested that go into/next to the IAC: One provides four point five volts, the other harness provides twelve volts.
3) Oily substance noticed around the hose ports coming out from the air filter unit.