Folks, I can't seem to get any response from FAST on my e-mails, so I thought I might copy it here, and see if any of you have any ideas: Here, for your amusement, is a copy of the e-mail I sent this afternoon, to FAST, detailing all my efforts and the mysterious results: Chris, I spoke with you this morning (Thursday, 7/13) regarding my ZZ-4 equipped Landcruiser. Let me rehash the history for you. This truck has a Davis Unified Distributor (HEI), and, for seven years, I had my tach signal coming off the Distributor’s “TACH” connection and running through the FAST “RPM Module” and to the ECU. Several week ago, the truck just quit while I was running down the highway (fortunately AFTER spending six days grinding around some EXTREMELY remote desert in Southeastern Oregon!). I had fuel pressure and spark but no signal to the injectors (checked with noid light). I spoke with one of your techs, and he told me that, while the instructions allow for connection to the HEI “TACH” outlet, as long as the “RPM Module” is used, it wasn’t a good idea and could result in unreliable injector signal. He said that the “RPM Module” probably burnt out. I tested the “RPM Module” for continuity, and it indicated and open circuit, so that theory seems reasonable. Your comrade strongly suggested that I go to a “CD Ignition box,” so I purchased the FAST E6. I completed wiring the E6 yesterday and took the truck for a couple of test drives. While it seemed to run smoothly, there was no power. After my first test drive, I came home and rechecked all connections (didn’t change anything) and went back out for another test drive. It ran the same, but after a couple of miles, it suddenly backfired a couple of times and then just quit. No amount of cranking would restart it. This morning, I called and spoke with you, and you had me check some things. While cranking, the handheld was indicating around 150 rpm (last night it indicated zero). You had me check the IRM, and it read 77! Thus, it appeared to be an interference problem. I rerouted all the wires as best I could, and it fired right up. I let it run for about 20 minutes, and I checked the IRM while it was running; it read zero! I shut the truck off, intending to take care of some other matters and come back for a test drive later. When I tried to restart it, it wouldn’t fire. I checked the IRM, and it still read zero. After sitting for a while, I tried to restart, and it fired right up. It was running for about five minutes when, all of a sudden, it just shut off, as though the key had been turned off. I tried to restart to no avail. I checked the IRM, again, and it read 27; I hadn’t touched anything or driven the truck, so I don’t know why the IRM would go from zero to 27. All my subsequent efforts to restart the truck have failed. I connected my noid light to an injector harness, and it indicated no signal to the injector. I pulled a spark plug wire off the plug, inserted a loose spark plug in the wire and saw no spark. This behavior is so random, it makes me wonder, again, if the problem could be the ECU. What confuses me though, is that I got no spark while cranking. Could a faulty ECU do that? I should note, that at all times with the key on, the E6 light is on. Could I have just been lucky enough to get a faulty E6 right out of the box?