I need help with the following codes if you guys can:

P0300 - Random/Multiple Cylinder Misfire Detected

P0302 - Cylinder 2 Misfire Detected

P0331 - Knock Sensor 2 Circuit Range/Performance (Bank 2)

Any idea as to where to start the troubleshooting? The plugs are Autolite 3923s with 4,000 miles on them and the wires are MSDs with 13,000 miles on them. The cap, rotor, and Accel coil are all pretty much new with 13,000 miles on them as well. I'm not sure what else to look at at this point. The problem is with the truck in my sig.

 

I would start by checking the plenum and the cat. If you have a cat.

 

No cat and the plenum repair was done a few months ago. I'll check again though just to make sure the repair didn't fail.

 

If the plenum appears ok, then check fuel pressure while driving also, by taping the gauge to the wiper arm or windshield so you can see it. Then the crank or cam position sensors would be next on the list. Check the wiring and connectors to them first though. And if you don't have a pinging problem I would toss the Autolites (atleast check them) and put Champions or the NGK's Aim recommends.

 

Thanks for the help. So whats the deal with the Autolites? I have never seen a negative post about them before yours above.

 

In some cases, they make the truck run slightly rough, and in a very few severe cases, I've read of them causing misfires.

I currently run them and am experiencing a very slight rough idle. I used to need them when my plenum gasket was broken (pinging), but now that that is fixed, I will be grabbing the NGK V-powers for my next change, see how they do.

 

Hmm, I guess that could explain it.

I talked to my mechanic buddy, who talked to his Chrysler mechanic buddy, who said that it could be a crack in the heads. Apparently, when the truck is used to just hauling around its own weight all the time and you load it down with a heavy trailer, this will happen. That makes sense to me because I had no issues at all prior to pulling that trailer. I noticed the initial problem up a hill while pulling that trailer. I was only driving 65 MPH (OD off) but I noticed a couple sudden, fairly "stout" misses and then it ran fine from that point on. By "fine", I mean that I didn't notice the rough idle problem until the truck was idling at a traffic light the next day. I hope it isn't the heads but I guess I could use this opportunity for some higher flowing heads.

 

You must not read much. I've posted several times that my truck doesn't like them.

 

Your didn't say anything about any plenum check?

 

What? Those aren't bolt on parts?