This is a new engine and has 13,000 so far.
It has plenty of power and pulls heavy loads fine but runs "rough" or "stumbles" at the idle. This only occurs at very low RPMs.
(I know that is a lousy description)
I thought maybe a bad plug or wire but that does not appear to be the problem.
It's very apparent when I shift into reverse for a slow backup but I don't think that has anything to do with the problem.
I thought maybe the fuel system but that's a WAG.
Any thoughts what to do next ???