Spark knock
Thread Starter
Teching In
Joined: Sep 2011
Posts: 8
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From: Houston
Spark knock Please Help! 2005 5.3 silverado, 99000 miles, changed plugs, wires, and mass airflow sensor, still getting p0300 code, above 4000 rpm you can hear spark knock on the driver side with the window down, and power goes away. I have an air raid cold air intake, and super chips tune, put the tune back to stock and the same problem, light flashing. Some one told me to check the cam position sensor......... any ideas?????????
TECH Fanatic
Joined: Aug 2006
Posts: 1,407
Likes: 63
From: Knappa, Oregon
P0300 is "Random Multiple Misfire" so the misfire isn't specificly isolated to one particular cylinder. Since you have replaced the plugs and wires you have eliminated the most common causes.
That leads us to the coils. Does your 5.3 have a coil pack, or a coil-on-plug like the LS1. A coil on plug means that each cylinder has it's own separate coil. A coil pack means that you probably have 4 coils running 8 cylinders, I am not familiar with the 5.3.
I had a similar problem on my V-6 that had a 3 coil pack. One of the coils was blown. The symptoms were similar.
If you have a coil pack, I would have the coils tested. If you have 8 individual coils then I don't know.
That leads us to the coils. Does your 5.3 have a coil pack, or a coil-on-plug like the LS1. A coil on plug means that each cylinder has it's own separate coil. A coil pack means that you probably have 4 coils running 8 cylinders, I am not familiar with the 5.3.
I had a similar problem on my V-6 that had a 3 coil pack. One of the coils was blown. The symptoms were similar.
If you have a coil pack, I would have the coils tested. If you have 8 individual coils then I don't know.
Just because the part is new does not mean it does not have a defect. Go Backwards. and double check connections and how tight the plugs are. IF you were not havin a coil issue before then it should not just all of a sudden happen.
I am willing to wager a gap is off, plug is not snug in the head, plug wires not connected correctly or possibly a defect in the part.
I am willing to wager a gap is off, plug is not snug in the head, plug wires not connected correctly or possibly a defect in the part.
Thread Starter
Teching In
Joined: Sep 2011
Posts: 8
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From: Houston
ok, first thank you for your suggestions, second you are not going to beleive this, my neighbor came over to see what I was doing, and said he had a similar problem, and gm had him put on new cat. converters. So I took them off and sure enough they were plugged. A hammer and a screw driver and an hour later, now this thing runs like a champ!!!! From a dead stop it smoked the back tires all the way through first gear!!! This truck didn't run this well when I bought it new! I guess now its time for some headers, and new exhaust. Thanks again!
