Hello Tim, I'm Billy and i will assist you with your problem
You seem to have checked everything, i need you to confirm the following:
have tried swapping coils?
and when you delete codes, do they come back at once or when engine gets warm?
Yes to both questions
Hard one;)...........So i suggest you proceed as following:
- do a wiggle test on coil wiring (wiring from coil to ECM) try and wiggle every wire on it's own while engine on, and listen to changes. Then check continuity, on each wire (aslo coil to ECM)
- flush engine oil (with a good flushing product), and put new oil and filter (as problem might be a faulty hydraulic valve)
- flush coolant, then put some block solder in it, run engine till cooling system cycles, and then leave to cool off overnight, and the next couple of days, flush again and put back coolant. (as the problem might be a compression leak; i know you perfomed a compression test, but the leak might only show when engine warms up).
Having done all of the above, i think we will have covered mostly everything (you covered most before coming here...), but there might be one more thing: you may try reprogramming or even changing ECM.
A confusing problem indeed, so Good luck!