Intermittent miss

[50_shooter]

Have developed a miss only noticeable at idle. It is a “blumph” sound every once in a while. Runs smooth for a few seconds then “blumph”. Run a few more seconds smooth then “blumph”. Almost like a intermittent backfire. When it does it the pulse width bounces around on the mini max from 400-100-800. No codes, no extra smoke, and runs good above idle. 157k miles on it now. Any ideas?

 

[sootie]

I sure hope for your sake you aren't seeing a lifter start to fail...they act like a skip or miss at idle.

Doesn't explain the rail pressure though.

 

[BIG JUICE]

turbo veins opening and closing?

 

[50_shooter]

Negative on the turbo veins. Mine don’t move.

I started it when it was cold and it had a couple of codes. Cylinder 1 balance and something else. It was not intermittent when cold. Every cycle it missed until it warmed up. Light gray smoke too. I think an injector is failing.

 

[Swaan]

Sounds like an injector .