Good news update frens, the broken fan was the primary source of my rough idle. I replaced the fan with a new one like the picture above with the 11 blades and the engine no longer shakes like it did before. its not a smooth as brand new but it definitely doesn't move like it did before.
kind of funny and sad after all this I never noticed the broken fan blade.
I checked the waterpump for play and it had none but i already know you guys will be on me to replace it and the fan clutch ASAP. I will try to get them replaced as soon as i can.
Hello socalK1500,
I really appreciate you coming back and closing the loop with the final solution to your rough idle.
This is one of those gotchas in remote troubleshooting that would have been avoided if we were working
shoulder to shoulder under the hood. With 1 set of eyes
most of the problems are found short term, and
all problems are eventually found when we dig a little deeper after the first few theories don't pan out.
(Or just serendipity when you are focused on something else and *then* you find the root cause of the first issue. BTDT.)
On the other hand, 2 or more sets of eyes in the engine bay at the same time usually finds the problem in the first outing or
two, for it's just the way these things pan out when a couple of mechanics are bouncing ideas off of each other...and there's the
unspoken race to be the one to ferret it out first. This tends to bring that extra layer of focus to the troubleshooting event. :0)
FWIW, all this is *not* wasted effort, for your documented troubleshooting session reinforces how a shake from a 'misfiring engine'
may instead be a shake from an ancillary part driven by the serpentine belt
superimposed onto a engine hitting on all 8. (more or less)
****
Listen, I know life is busy, and you aren't here in order to provide me with troubleshooting entertainment, but
I for one would be really interested in what kind of misfires (if any) are still being logged after fixing your fan.
I really want to see all zeros across the board, but if we can't have that, then documenting what you've got will at least give us
a reference to better judge future changes against.
Best of luck keeping your GMT400 on the road.