If I let my truck idle for a few minutes it throws the check engine light, I hooked my programmer up to it and it said it was a random misfire and then I pulled up the graph and showed the #7 cylinder was misfireing, you can tell truck doesn't idle smooth and doesn't run like it should and its drinking gas real bad I never had any problems, it all started after I broke the pinion yoke and driveshaft, I put the 150 pills in it and I went 8.71@83 then on the way home the pinion yoke broke and driveshaft broke when I got it out of the shop I could tell it wasn't running right and since then just been getting worse and worse any help would be very much appreciated!!!

 

did you check the spark plug wire for #7? It happened to me once, several months after I put on headers.

 

Pulled the plug yet?

 

Changed plug, still has a misfire not as bad but still has it, I retuned it back to stock and just made it right for my gears, another thing I heard is a big vibration can mess with the crank sensor which can cause a misfire so I'm thinking it could be that when my pinion yoke and driveshaft broke it was a loud boom so maybe it knocked it out of whack? Or time to build a 8.1 !!!! Lol

 

Ok thought it might be the crank position sensor but was told truck wouldn't run if it was bad so now I was told could be the idle air control vavle but I did unplug my mass air sensor and it didn't effect anything still idle the same??????

 

Wondering if you have figured out your problem on #7 cylinder??? I am having the same problem but im getting a P1174, P0742 codes.