My truck was working perfectly fine then I turn it off for a half hour and then the key will turn but nothing happens, just the lights on the dash come on, it is a little difficult to turn the key back to get it out.

Found Leaking vacuum hoses, replaced them..replaced the fuel pressure regulator

I want to do away with the fuel injection

Appears to be battery or alternator but concerned how that prevents the vehicle from moving

The car has sat a lot outside for over a year. It hasn't started for 6-7 weeks, 2 weeks ago it started, I filled it up, next day it wouldn't start and hasn't since. The car cranks, but won't start. Battery replaced 5 weeks ago. Lights on are check emissions, check TPMS. Took it to a mechanic, he said the main computer won't communicate with the diagnostic machine. My friend thinks its old gas and I should put dry gas in, the mechanic thinks it could be anything up to the main computer. The original main computer was replaced around 60k, so this is the second. Any thoughts would be very helpful.

The ECP light is on along with the engine light. The car loses Power and starts jerking around when I try to accelerate.

I Don't know if its the oil pump or oil pressure switch. only help?

is there a problem with power steering.

I have no pulling or anything while driving the car.

I've checked my fuses.I should also say my heater an stereo won't work also