Engine starts to miss / rough after 5-10 minutes with gas odor after 15

[jmauld]

I tend to agree but I am struggling with this one. If it is electric......it is affecting all the cylinders the same since all the plugs are black. So it keeps running but the secondary spark is weak enough the plugs don't fire all the time? That would point to the pickup/coil distributor cap problem.......but it would be happening all the time not just when it was under load.

I still would like to know the fuel pressure. And I would like to understand what the ECM thinks is going on.

There have been a lot of part changes which also complicate the picture.

Perhaps the OP can share when the last time this engine ran correctly and give us a little more history specifically around when it started to behave like this. For example was it running well before the water intrusion?

A weak spark can get blown out under load and run perfectly fine at other times

 

[scoflaw]

Use a paper clip between A and B to manually put it in service mode

Get an accurate read on fuel pressure it could be too high

 

[JohnEGraham]

Agree with checking fuel pressure. Phasing wasn't a thing with that ignition system OP is running. Was it a new distributor or used?

its a new distrubuter...