Here's the lowdown - '87 K5, 350 fuel injected, new engine installed in January. Removed AIR and A/C upon reinstallation. I finally got it running properly (TPS wasn't seating properly, would die when putting into gear), but the electrical system isn't charging properly. I had it out, driving around for about 20-30 minutes and realized too late that the Volt gauge had been constantly dropping. The truck died and would no restart; it acted like there wasn't enough juice to turn it over. I had a voltmeter handy, and it read 11.8 - 11.5...something around that number. Wouldn't start for anything. We tried jumping it off of another car, and it would start, but as soon as I removed the jumper cables, the truck would die. The alternator has been tested 2x, once at an Autozone and again at a Napa. The starter and solenoid are new. I have replaced the fusable links near the starter. The battery (Red Autozone version) was replaced recently and seems to be holding a charge well. I had bought a new battery in January/February and returned it in April when it would not hold a charge. I don't know, but maybe my problem is killing batteries too. Could this be caused by something wired up incorrectly during the engine installation? I posted this thread a little bit ago, but didn't get any answer. The truck runs with that wire as a positive, negative or disconnected. I'm stumped... any thoughts?