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5.3L Mystery
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KAM_GM
New User
| Posts: 2
| Joined: 06/10
Posted: 06/15/10
03:20 PM
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I have a 2005 GMC 1500 4wd with a 5.3L. I'm having a hesitation problem that no one seems to be able to pin point. It only hesitates when it's in drive and i slowly pull away from a stop. All the computers it has been hooked up to say it has a random miss fire. so far i have unplugged all of the o2 sensors with no change, have swapped the maf sensor with no change, and have replaced the crank sensor with no change. beyond the things i've looked at no one seems to have an idea. if anyone has any ideas i'd like to hear them.
Thanks
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Posted: 06/15/10
08:50 PM
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random misfire... got a code?????
OK... make sure that everything is hooked up properly... nothing unplugged you have describe will make a random misfire.. hook up the scan tool.. scan the codes.. write them down... then clear them...
i would first start by numbering the coils.. taking each one off and examining it along with its individual spark plug wire... look for high voltage leakage.. little dust circles.. little white dots.. this indicates that the coil is leaking high voltage to ground..
i would also OHM the spark plug wires... yes.. they are short.. 1,000 ohms per inch MAX.. set the meter to 200K ohm scale.. each wire should display less than 10 on the scale..
examine the boots for leakage..
take out the spark plugs.. examine them for fouling.. if any seem to be fouled.. replace them..
be sure to use spark plug anti seize on the threads...
be sure to use a dielectric tune up grease on the insides of both ends of the spark plug wires.. this seals in high voltage..
there are several other reasons for random misfires... coils.. spark plug wires.. spark plugs are the first to check.. it could also be clogged injectors.. unplugged injectors.. vacuum leaks.. exhaust leaks...
do you have any leaks between the throttle body and the maf flow sensor.....
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KAM_GM
New User
| Posts: 2
| Joined: 06/10
Posted: 06/23/10
06:41 PM
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Well the mystery is solved. I was talking with my friend who has seen everything strange with these engines and he said that a lot of the 5.3L engine had some issues with the injector harnesses being a little bit loose and can cause the random miss fire. so I checked it out and havent had a problem since. Thanks for the ideas anyway though
KAM
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