I am having cylinder misfire at the #3 cylinder. Weird part about it is, it only happens when I turn the AC on full blast. When I don't have the AC on I dont have the misfire. I turn the AC on to low speed, I dont have a misfire. I turn the AC onto its highest setting, I have a very hard, pronounced misfire! Its a very noticeable misfire and shakes the truck! I got a log of it so you all could see it. I checked all my spark plugs wires thinking one came loose but nope, it still does it. Any suggestions? I believe this issue is going to be mechanical right? Probably a spark plug? How do I know which cylinder is #3 from looking at the engine?