Troubleshoting Engine Stumble, It's alive!!! Options

[ericread]

I finally got back from Las Vegas, so here I am in SoCal, still trying to troubleshoot my engine stumble.

BTW: TPS is disconnected, and I have pinched off the cold start valve fuel line.

My engine seems to do well when the engine has cooled. By cooled, I mean for about five minutes or more, say at a gas station. For the first five minutes, the engine runs OK. After about five minutes of driving, the engine misses pretty badly whenever I let up on the gas. During acceleration it feels strong, but once I let of the gas to maintain driving speed, the stumble - missing returns.

So I drove my car for a while to make sure the engine was warm, and returned to my garage. I unhooked the CHT, and the engine was unable to start - engine flooding. That makes sense to me. I grounded the CHT wire from the wire bundle to the ground of the battery and drove for another ten minutes. No change.

I re-attached the CHT and decided to see what was really happening (which I should have done at the start). At idle, if I disconnect the number 1 or number 4 spark plug, no difference in the engine idle. When I disconnect either 2 or 3, the engine barely runs. As I reattach #1 and #4, I see spark. So it would appear to me that cylinders 1 adn 4 are not getting fuel?

Since I have spark to cylinders 1 and 4, this would normally lead me to the triggers. But the triggers fire 1&3 together and 2&4 together. So that makes no sense to me either. Add to that a FI injector grounding issue should affect a single side, which would be 1&2 or 3&4.

So what would cause this issue? Any thoughts?

Eric Read