ok so my brothers 1995 dodge ram 1500 5.9l 4x4 is detonating cylinder #8. what could it be? my dad has changed the cat because the cat was bad and he was driving around with the bad cat so could the driving around with the bad cat have made it so the #8 cylinder is detonating? i was thinking that the knock sensor could be gone but i was looking on autozone and they do not show a knock sensor for this model so i am stumped i have no clue what it could be? any suggestions???

thanks,
cam

 

https://dodgeforum.com/forum/2nd-gen...um-thread.html

Probably need to check out the plenum and PCV valve.

 

^What he said.
There's no knock sensors that's why autozone doesn't show 'em, so don't worry about that.

You're brother's truck is probably a little low on oil? If the plenum is blown, it will cause loss of oil, detonation, a bad cat, misfires, lack of power, etc... the new cat will go bad (after a while) if you don't fix the plenum/pcv, if that's the issue. So definitely look into it.

 

Looks pretty much like the plenum...So

 

From everything ive read id 4th the motion of plenum two main sighns... Spark plug 8 and clogged cat