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P303 random misfire code #7 cylinder!

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Old 09-18-2010, 12:46 AM
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Default P303 random misfire code #7 cylinder!

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!!!
Old 09-18-2010, 10:55 AM
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did you check the spark plug wire for #7? It happened to me once, several months after I put on headers.
Old 09-18-2010, 10:57 AM
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Pulled the plug yet?
Old 09-18-2010, 01:53 PM
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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
Old 09-18-2010, 06:22 PM
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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??????
Old 12-13-2012, 11:50 PM
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Wondering if you have figured out your problem on #7 cylinder??? I am having the same problem but im getting a P1174, P0742 codes.
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