Ok so this is about the oddest thing that I have seen. Background 2056 with electronic ingnition. 74 matched components per Anders. AF meter installed.

Had issues with car going lean but adjustment to MPS resolved. Recently changed ECU to 74 version. All seemed good. Now I can drive car. Runs great! But at times it just dies. No change on the AF readings prior to dying but it won't start after it dies. Puts out white smoke like it is flooded. Wait 5-min it starts and all is good for 10 minutes. Repeat.

Fuel pump is in front so no vapor lock. Checked electrical connections and they seem good.

All I can think of is the ECU. Is this possible?

Ecu is possible, but check your cht sensor first. I had a similar problem last year. Found my cht a little loose.

Any chance the connector from CH temp sensor to ECU is not making good contact? Might be faster to plug the old ECU back in.

I removed and installed seems tight. Will check again to be sure.

Mike, CHT is my first thought as well. What condition is your wiring harness? The CHT itself may be good, but if the connection to ECU is sketchy then things like this can happen.

Rob good thought. I did have to repair the CHT wire some time back. Will check it