I keep getting the P0300 code but only when I'm idleing. I have the POS Bosch+4 (I didn't know at the time). I was wondering, can these be the cause. I know if one is cracked it can but what about a "good" one? I know there are other things I can check also but I felt I should start here.

 

My truck had that code and it was the crank relearn.

 

Thanks. I've already had the crank relearn done.

 

Multiple misfire code, could be a number of things. I'd lose the Bosch plugs just for piece of mind and start from there. You can pick up a set of NGK TR55's for less than $2 a plug.

 

I picked up some TR55s earlier this morning. If I have time this afternoon, I'll change them out. If not, I'll do it tomorrow when I change my front wheel hub Thanks for the help. I hope it works.

 

Im having the same problem. I changed plugs, wires, fuel filter, and now I'll be changing the cats. how do you do the crank relearn?

 

For the crank relearn, I hooked up EFI Live to his truck and performed it last summer.

I've had a pretty bad misfire at idle on all cylinders caused by the truck going lean randomly. Think I tracked mine to one of my intake tubing clamps not being completely tightened down.

 

I believe the cam is causing your false reading on misfires. I did in my case and a few others from what I hear.
You can try upping the misfire time or do what I did and just disable it.