Josh1738
To anyone who had this problem i have the code p0308 on my 99 2500 ram pickup whit the 5.9L did a Complete tuneup spark plugs wires and cap and rotor is still getting the code Took out spark plug on cylinder eight and it seems to be wet and I do have spark and fuel check the cylinder with the camera and it looks like there’s oil and fuel I did a compression test all the cylinders were roughly 150 psi if anyone knows what could be the problem please or suggestions

 

Possibly bad injector, dumping too much fuel?

 

would a bad plenum on the Intake would cause that code and a misfire to come out just on that one cylinder?

 

Depends on where it's blown..... there is no fuel in the air stream, it gets injected right at the cylinder.... however, there would be unmetered air entering as well, which might lead to a lean-burn miss..... What generally happens though with a blown plenum, is the cat starts clogging up, and the rear cylinders run hotter.... and start misfiring.

Try swapping the injectors on 6 and 8, see if the miss follows the injector.

 

I’m having the same issue on my ‘99 ram 5.2L on cylinder 8 only, and I also had the same issue with a 3.6L I had. I diagnosed the 3.6L on cylinder 3 to be the plenum plate bc after I put seafoam down the throttle it starting hissing after cleaning up the gunked up oil in the plenum. I tried swapping my plugs on my ‘99 today and it didn’t fix my issue, I’m thinking maybe it’s either an injector or my plenum plate.