Back story: the "old ranch truck" is a dependable 4-banger that almost never goes 30 miles from out-in-the-sticks home--until I took a load of grape stakes down the 110 Freeway, and that's when it took a dump in the middle of the rush hour LA traffic--worst possible place. So, I have to get towed and mechanic replaces melted CPS, coil, pick up coil, rotor & cap. Truck runs like a champ for the next two weeks then...no spark. Gauges work, no codes showing, and I'm thinking that it's the computer, because I'm just *made* of money....

Any thoughts? I've read every post on this I can find on this topic. Perhaps a voltmeter test on ECM that a not-good-with-electronics guy like me can do?

Many TIA!!

 

on the coil, take a voltmeter or test probe and measure across the 2-pin coil connector. You should get a 12 volt pulse with the engine spinning over.