Just wondering if anyone has had any experience with this, My truck runs great at full throttle but part throttle cruising 65-70mph cuts out and I get a trouble code p0300 multiple cylinder random misfire. I've replaced cap, rotor, plugs, wire, coil, fuel pump. Running out of ideas. Could it be that I got all my parts at autozone instead of ac-delco? I've heard not all distributor caps are the same. Anyhow I'm really not wanting to pay a dealer to look at this thing so any help or ideas would be greatly appreciated.

 

this could be some help mine had a broken coil wire drivers side rear plug, after I found that problem another one developed not related fuel pressure switch was bad, however I did smell gas while under the hood. That was a real bugger to figure out... there just ideas. also check with my GMLINK.com ask if there is any service bulletins that you should be aware of you might get lucky and find there was or is an issue about the code your getting.