#5 and #7 misfire

[rAiNTwist]

You need at least a compression check, and preferably a leakdown test. Head gasket is suspect. All of your symptoms support a head gasket failure, and one of the key diagnostics for head gasket failure is that all of your other efforts have not made any change.

I have the same suspicion. I bought a CO2 detector that goes on the coolant reservoir that tells you if your head gasket is bad or not (that’s if exhaust gases are getting in the coolant) and that should be here later today, so I’ll let you know what I find on that. It’s at least worth a shot before I start throwing parts at it.

 

[rAiNTwist]

Many of the aftermarket distributors come with the non-adjustable dist hold down. Swap with the factory one and that should remedy that issue, as well as CMP being one of the most misdiagnosed as something else problems. A little more testing and we should be able to pinpoint your problem(s).
Minimum tool list- scanner, fuel pressure guage, spark tester. Total under $100.
First suspect on misfire is dist cap on these. Just sayin. Good Luck!

Wouldn’t CMP affect all cylinders though, or at least a bank and not just 2 cylinders?