I recently had headgaskets go on my diesel, I pulled the olde girl apart, replaced the head gaskets and seals. Got er all reassembled fired it up ran smooth as glass no pushing out coolant or hydrolocking anymore. After about 5 minutes of idling she starts to just randomly missfiring, sometimes for 10 seconds sometimes for a few minutes, it can get bad enough to the point she starts to bang and smoking like crazy, I did do 3 oil changes since the head gaskets in the time of 3 hours, the first two drops the oil came out with a bunch of gray crap that would show if you disturbed the oil. The third time it came out just black. The oil pressure seemed low too me at 14lbs and was still dropping pretty steadly. The only other thing that was wierd when I pulled the oil fill cap I could hear something squeaking. The engine had a bunch of sludge and like other parts of the truck showed since of it had sat outside for a long time before I got it. My return lines are leaking, severly but it should cause it to miss all the time. The truck has 232,000 km on the odometer but the speedo dosnt work. When I had the heads off it looked like it had more around 400,000 on the engine. The truck is orignal ip and injectors.

 

Gray stuff in the oil and a squeaking noise from the engine could be a bearing failure.

 

You won't have a misfire. I see you're a senior user so you probably mean something else. Misfire has to do with ignition on a gas engine. Theoretically you still could have something similar. But you would more than likely would have a dead cylinder.

 

I do since I will have the engine runing smooth and visually and hear, a cylinder(s) fire incorrectly for a short period and than it returns to running correctly.

 

I would have to say it's injector related. You're either not getting fuel to that cylinder (intermitantly) or you're losing compression. Now you could have a piston ring that's staying compressed at times. Carboned up. I would put a new pump and injectors on it. With 400k I'd say you're due. Again I'd say it's fuel related. If you think your rings are frozen up from all that gunk you got out of your engine. You could try soaking them with something. Pour it into your glow plug holes or injector holes. Trans. fluid, penetrating oil, brake clean. They used to make this stuff called TDC cleaner, but they pulled it off the shelf because it was to caustic.

 

Ive decided to pull and do a major service. I think that would be best with all the **** that came out. Hopefully its just a bearing, I dont feel like blowing this olde girl up just yet. I am doing a compression test before I yank it.

 

Good news did a return line kit clean the miss up runs great till 170 degrees than runs rough again and diesel knocks and smoke. Oil pressure holds steady at 13/14 psi at 900 rpm. Idle has always bein set high on the pump. Whats considered excessive smoke out the cdr and oil fill, I understand a small amount is normal, and should clean up, mine at temp smokes pretty steady at any temp.