Code P0307- Mysfire Cylinder 7 is driving me crazy!! - Chevrolet Forum - Chevy Enthusiasts Forums

Code P0307- Mysfire Cylinder 7 is driving me crazy!!


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  #1  
Old  February 21st, 2012, 6:15 PM
Code P0307- Mysfire Cylinder 7 is driving me crazy!!

Hey guys, i recently bought a 06 chevy silverado crew cab 5.3L 4x4 and it came with the check engine light on, but i thought it would be easy to take care of it by replacing the spark plugs, spark plug wires, cleaning out the throttle, but i already did those changes and the scanner still reads the same code. does anybody know what the problem might be?

  #2  
Old  February 21st, 2012, 8:20 PM
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swap a coil from another cylinder. clear the code and see if the misfire follows the coil.

there is a tsb for poor connection to the power feed to ignition coil feed circuit so if it doesn't follow the coil for the above test...check for spark at the spark plug wire for #7. If no spark check for power to the coil with key on.


Last edited by tech2; February 21st, 2012 at 8:27 PM.
  #3  
Old  February 22nd, 2012, 6:54 PM
Hey man, i tried swaping the coil from one cylinder then i cleared the code, but the misfire remained at cyl # 7. the spark plugs and the wires are brand new. what else could be the problem? do you think i should check the injector?

  #4  
Old  February 23rd, 2012, 5:28 AM
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Tavo Govea 
Hey man, i tried swaping the coil from one cylinder then i cleared the code, but the misfire remained at cyl # 7. the spark plugs and the wires are brand new. what else could be the problem? do you think i should check the injector?
check for spark at the plug wire for #7 with a spark tester

  #5  
Old  February 24th, 2012, 12:56 AM
Good advice from tech 2.But i had the same issue.Replaced everything,Map,all 4 o2,plugs,wires,idle control,and so on. Have you checked ur fuel pump. Should be at min. 55lbs. One pound under and it will cause A misfire code. Could of saved my self A LOT of money if Id checked it first. Ended up that was my problem. You will need a fuel pressure Gage. Got one from parts house. Good luck

  #6  
Old  February 26th, 2012, 7:29 AM
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Get a small peanut bulb and pull 2 wires away from bulb then plug the bulb into injector connector and start engine should see dim flash every time injector fires that will verify power and ecm groundind circuit.

  #7  
Old  February 26th, 2012, 7:34 AM
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Also unplug vacuum line off fuel presure rail while running and see if it spits a little fuel out.that was a common problem.regulator is alittle bigger than a quter and is on dr.side about 12" from back of fuel rail


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