Mitsubishi Repair: Car cuts off, flash burn, car cuts

Question
I have a 1992 Eclipse, 1.8L, GS, manual trans.
I first had a problem after I came back from the Beach last June. I was driving the car and it just died. I checked the spark and found that there wasn't any. So I replaced the distributor with a new one and the car ran for a day or so and died again. I removed the ECU and discovered that it had a flash burn in the unit. I went to a local Pull a Part an found a ECU for my car that matched and installed it. It ran fine for a day then started loosing all power to the motor. I took it to the local dealer and they had it off and on for about a month and claimed that there was nothing wrong with the car. The last time the dealer had it they replaced the igniter relay and on my way home the car quit running again. It progressively got worse to the point that I can't even drive across the street without it dieing. I thought that the ECU I had purchased at the yard was defective so I bought a rebuilt ECU and installed it. It ran great for 19 min. Then died again. I have found that every time it dies the Tachometer looses power and drops to the bottom while the car is still in gear driving. The engine looses all its spark and won't crank back up from 10 mins. to sometimes 2 hrs. I really like the car. It's in better than excellent condition, and when running, runs and drives exceptionally well. I really want to fix this problem but can't find anyone who can tell me what the problem is. So please if you know or can find out what is causing this, I really would like to know.

Answer
Paul,
Intermittent starting and stalling like you're experiencing does sound like an eletrical problem.  It's tough for me to even make suggestions to the problem since you said the dealership had it for a month and couldn't find the problem.  This could be a problem with the ignition coil/distributor assembly.  I believe the crank/cam angle sensor is part of that assembly, and it may be malfunctioning.  There are a number of sensors tied into the ECU, that if they are malfunctioning, could be telling the ECU to turn off the fuel and ignition.  There may be a problem with the eletrical harness on your ECU.  If your original ECU was fried, there could have been a short circuit in the system and is still causing problems.  If you can, you should see if there is another dealership you can take your car to and make sure they test all your sensors; including your ECU and harness.
Good luck!