I have a 1993 ford ranger 4x4 with a 4.0 v6 engine. It died and would start back about 8 months ago.Today I started testing it and hooked up fuel pressure guage and nothing. So, I pulled the pump and replaced the pump/hanger assembly and drained out all the old gas and put fresh in it. It had good fuel pressure but wouldn't start. It didn't have any fire. I changed out the coil pack with another one I had laying around off another motor, and still nothing. I pulled out the ohmeter and tested the voltage and fuses and everything checked good. I then pulled off the panel to expose the ecm and inspected some wires and then climbed under the truck and ran my hand up the wiring going into the crank sensor. I didn't find anything. I then thought, what the hell, I'll try it 1 more time and boom… It started right up and ran, but it won't go below 3000 rpms. It will not idle. So, I proceeded to check for vacuum leaks and nothing was found. I didn't smoke test it to see if the upper intake's leaking or anything. I'm thinking maybe a idle air control valve, tps, vacuum leak, or an ecm problem… And why did me fiddling around with some wires cause it to start? I'm at a loss and am thinking an ecm prob since I did move it around a little. Any ideas?