New situation(we don't have problems).
Coming home at night noticed(becauce of lights behind me) that the truck was smoking on acceluration. In day time looks like grayish smoke. Then developed a knock on pass. side. Mach listened to it and said that it sounds like a rocker arm or valve spring only on one cylinder. Worse case, bad cam. Has to tear down to find it.
Any thoughts or suggestions?

 

might be an injector going bad and the fuel is not being sprayed properly. I'd check that first by shorting out (breaking fuel line loose) the injectors. The one which doesnt change is the bandit. Pull that injector and look at it. The tip may be gone or it has a broken spring inside and letting the compression push fuel back. You can also remove valve covers and see if one of the rocker mounts are broken letting the push tube do nothing and will cause a miss. Malcolm can get in here and add to the diagnosis. Good luck and keep us posted.

 

Will do that but the truck seems to have all the power that it had before knocking.

 

i just went thru about the same thing.found the pushrod bent up and the rocker loose on the intake valve on number 7 which is the last one on the pass side.i.e no compression about put a hole in the valve cover.

 

You noticed the smoke at night, what color is it during the day?

Do what bilder said, see if you can find which cylinder has the problem. If you can't make the knock go away then pull the valve cover and look for a problem with a pushrod/rocker arm/spring. If you still can't find anything wrong.... well, we don't really want to go there yet.

 

Will do, In the day time the smoke was a dirty gray but only noticable on accellateration, not a lot but it's there. Note, at idle there is no knocking but when reved up it appears and also in gear on accelarting and constant driving but not when I back off and let it slow down.

 

New situation. Let it park for 2 days. today took it about 2 miles to storage center to take off the snow plow equip so it will be easier to work on the engine and no knocking and no smoking. Could this be a stuck valve, lifter, or something that worked loose? The mach is about 25 mi away. Planning to drive out there tomorrow. If it is OK by the time I get there, I'll turn around and drive home and save the money.

 

sounds like an injector prob.you should have em checked out,if it did it once it will probably do it again.

 

Update - Well I put over 200 miles on it w/ no knocking. Do remember that I ran a tank dry(found that the guage isn't that accurate) the day before. Mayby some junk got stuck. I don't know but can't fix what isn't broke.