I have attached a log file. Recently completed swap. It's an '02 8.1 but is essentially the same as 4.8/5.3/6.0/etc. Im wondering if anyone has ideas as to why i'm having a misfire that's almost exclusively limited to idle. It's obviously just the #1 cylinder. Raise the revs up a bit and the misfire all but goes away. Thoughts?

 

Also, i don't know why the log pauses every several seconds. This log is the first time that's happened. Previous logs don't have that trouble, but this is the first time i set up the config in this way. So I'm suspecting its just the way i did the config, or a laptop issue.

 

Check for a dirty injector. It might stick at low flow rates but clear at higher flow/pressure

 

The engine did sit for about a year before the swap. So that makes me wonder.

 

Maybe run a bottle or two of Techron in the tank and drive the **** out of it. That MIGHT clean the injectors.
3 years ago I bought an 04 Tahoe with 160k miles on it and ran some thru it. It did make a difference. Now I run a bottle thru once or twice a year as a preventative measure

 

Check the compression?

 

What the plug in #1 look like?
Condition of spark plug wire?

 

I would swap that injector with another cylinder and see if the problem follows the injector.

Could be a spark plug maybe. Could have been dropped or cracked during installation or fouled by bad fuel. My '02 Camaro SS that never gets driven will foul plugs in 5 minutes if I let the fuel go bad.