NickG

This was the exact same thing I said. However, you have to remember that your problem is intermittent! Of course it's going to test okay most of the time.... which sucks.

I am totally in agreement. It bugged me when I would find something that I thought might be similar to my problem, and the person would never come back to post their solution. Hope this helps someone!

It was the ignition module. Replaced it and it works fine. Hasn't died in several days.

My problem turned out to be the ignition module.

Has anyone tried to do a cruise control install on older L28s?

This sounds a bit like my problem, though not nearly as advanced. I quite fear that mine is due to a short in the wiring harness... which would ultimately suck. http://forums.hybridz.org/showthread.php?p=1008585 Sometimes mine will die and the tach will drop to 0, then immediately come back to life and spring back up. Sounds just like what you've got going on. Oh yeah... I don't have a solution.

I do have a FSM. I have replaced the ignition switch 3 times. I can't actually test the wires themselves because the issue is intermittent. The wires may test fine while I'm testing them but could lose connection while driving (causing the problem). I'm starting to think it may actually be the ECU... which is lame. However, the problem occurs whether its 40deg outside, or 120deg outside. It happens 30 seconds after the car has been running cold, and it also happens after 45 minutes driving at 70mph. There's no consistency in that regard. I printed out the wiring diagrams on 2ft x 6ft paper and followed just about every line related to the coil... but the weird thing about it is how jarring the wires or switch would cause the car to come back to life. This suggests that it is some sort of loose wire.

I replaced the air flow meter in a 76 280z 3 times because I was out of gas. The people at my local import parts store were pretty upset that I told them they gave me 2 units that were faulty... and it turns out that sending unit in my tank was bad. So I died on the side of the road one day, thinking that I had 1/4 tank of gas. Had to get towed, whole nine. Troubleshot everything I could before I came to the conclusion that it was the AFM (would start but ran chuggy, and would die, etc). Eventually I was like... well maybe it's bad gas? So I put some gas in.. problem disappeared. I realized then that I was just out of gas. I had the car off the road for 2 weeks. MEGA facepalm.

Thought the topic would grab some attention. I've got a 1981 280zx non-turbo, auto tranny, with about 124k miles on it. So for about 3 years now, the car would randomly shut off while I was driving. Didn't matter how fast I was going, what the temperature outside was, the time of day, how much fuel I had, what day of the week it was, what mood I was in... The solution was to just turn it over again and it would start right back up. Usually, I could be doing 70 on the freeway, and it could die, I could put it in neutral and coast while I restarted it. Or I could be sitting at a stoplight and the same thing would happen. Over time, it got progressively worse. It wouldn't immediately start back up, it might take a few tries. Eventually it got to the point where sometimes I couldn't start it back up. I got it towed 3 times, and by the time I got it back to the house... the car would start fine. I could not figure it out... there was no consistency. I replaced the ignition coil, the fuel pump, the fuel filter, spark plugs, spark plug wires, distributor, ignition switches. Nothing helped the problem. After doing all of this, and leaving the ignition switch dangling beneath the steering wheel while driving because I was in the middle of operations... I was driving along, and the car died. I lifted the ignition switch to put my key in to start it, and to my surprise, just by MOVING the switch, the car sprung back to life as if it had never shut off. So I drove around for a year like that... shaking my ignition switch whenever it would die while I was driving. Now... it's worse. Not even that works anymore... immediately. I may have to sit at the side of the road shaking wires beneath my dash for 5-20 minutes hoping that some magic will fix it. And so far, it has... but I predict that the condition is getting worse and soon it won't. Now... onto odd symptoms and things I've noticed. When the car dies, and I attempt to restart it, the starter motor works. There is no spark when it is in the "no-start" condition at the coil. The tachometer does not even jump when the starter is running (it does when it starts correctly.) I have run a wire directly from the BW wire at the ignition switch to the coil, thinking there was a discontinuity in the harness. Did not work. I've posted about this problem on a few other forums. It boggles me. Anyone have a clue?