studballs

iTrader: (1)

What can be the causes of a clean spark plug. My engine had been running really bad, backfiring, running extremely rich so I changed o2's and plugs with no real improvement. Pulled the plugs today after about 20 miles of driving it, hoping to get a check engine light and this is what I got. Cylinder 1, 5 and 7 look good but cylinder #3 looks like it's brand new. Can this be the cause of a bad injector or coil? Thanks guys.

slap(A)hoe

iTrader: (2)

i would guess and say coil is gone out on that cylinder

gMAG

iTrader: (1)

After running the engine, did you notice wet gasoline on #3 plug?
If no gas, I would connect a NOID light to the #3 injector harness plug. In fact, I would connect the noid light anyway to check if that injector is working. If NOID shows it working, I would then look at the coil.
Do you have a spare spark plug & boot? If not, you might swap the plug & boot from another, then see if things change to #3.

studballs

iTrader: (1)

Well just for the hell of it I removed the valve cover on that side to find the #3 cylinder rocker arm cocked to the side with the rocker bolt unthreaded and stripped from the cylinder head. Not sure exactly how that happened. Push rod shows no damage or bent in anyway. Gonna have it flatbed to the shop and have them helicoil the bolt hole. Thanks for the suggestions guys!

Paul Bell

iTrader: (9)

What year & how many miles on this engine? Mods? Stick or auto car? Been over reved?

gMAG

iTrader: (1)

Good 'catch'!
It was fortunate that nothing was major was damaged.