Hello,

I was trying to find a noise that seemed to come from the serpentine belt when revving the engine, but after many repeated tries of revving the engine, I did not find the location of the noise.

Anyway, after the repeated revving of the engine, I got a P0308 along with knock/ping sound from under the truck and the sparkplug from cylinder #8 had no gap which made me think the internals went out.

I checked for compression and all the cylinders were (120 PSI +/- 3).
Also checked for rod knock by turning the engine slightly past TDC and using a screwdriver to feel for any play, but none was present.
Replaced cap/rotor and wires(cap/rot were in bad shape), but the P0308 still showed up.
the injector seemed to be working because I felt the pulse with my finger(I assume a better test can be performed)

Any ideas of what could cause the misfire in cylinder 8

 

Did you actually replace the spark plugs? Or did you just gap the existing plug? It's either spark, compression or fuel. Which engine are we talking about here?

 

I apologize. I see which engine it is in the title. 120 lbs compression seems pretty low to me. My 99 5.9 runs about 165. But 120 won't cause a misfire.

 

How's the plenum?

Did the plug in number 8 get hammered??

 

I did replace the sparkplug when I took out the old one the ground tip looked like it was hit(no gap). I was checking the plenum today an it does have some oil 3 pictures should be attached what do you think.

 

Yeah, plenum is blown.

Did changing that plug improve its attitude at all?

 

I did replace the sparkplug, but the check engine light came back after that I swamped fuel injector 8 and 2 and cleaned them with carburetor cleaner and a 12v source to open and close the injectors. The check engine light did not come back. After further inspection the knocking sound seems to come from the transmission right where it connects to the engine.

The following link Points out the shift linkage, but I don't hear or a see any vibration coming from it.
http://dodgeram.info/tsb/2000/21-12-00.htm