murphs

I need a little help with a misfire. The vehicle has 130,000 miles and has new plugs and plug wires. I have swapped coils and injectors and the miss stays with cylinder #3 which has 150 psi. on compression check. I have also disconnected exhaust in front of converter so I have no excessive backpressure. Any help will be greatly appreciated. Thank you.

Royalwapiti

Sorry, I had the same and after doing the plugs and wires still had the code so I changed out the #3/6 coil and the problems went away.

If you haven't fixed it, check the fuel injector.

If you did fix it what was the problem?

Thanks

murphs

The cause of the intermittent compression test results that got progressively worse and the misfire on #3, was a rocker shaft nut that was backing off of a partially stripped stud from a previous repair. This is probably not the most common fix but can give you another rabbit hole to go down. The compression tests finally gave way to being absolutely poor every time I checked and this is what was found.