Spark plug issues!!!

[cmyoung2007]

I have a 2004 Chevy Tahoe LS 5.3L V8 Flex (VIN Z TYPE), and I just replaced the spark plugs and wires. I’m now having a code being thrown and it is p0300. Does anybody know what the problem could be?

 

[Doubeleive]

I have a 2004 Chevy Tahoe, and I just replaced the spark plugs and wires. I’m now having a code being thrown and it is p0300. Does anybody know what the problem could be?

double check your work, pull the plugs and wires if necessary, look at the plug gap, re-install to I believe 14ft lbs. (might want to verify that, just going off of memory)

 

[cmyoung2007]

double check your work, pull the plugs and wires if necessary, look at the plug gap, re-install to I believe 14ft lbs. (might want to verify that, just going off of memory)

I’ve done that twice now. I bought new spark plugs online. I installed those and it was misfiring, and then I bought NGK’s from AutoZone and it’s still misfiring, but not as bad. The original spark plugs that were in it before all of this was Acdelco Spark Plug 41-110. I did some research on them and it said that those weren’t even a fit for my vehicle, but they worked fine and there was no check engine light or misfiring when they were in the vehicle.

 

[Doubeleive]

I’ve done that twice now. I bought new spark plugs online. I installed those and it was misfiring, and then I bought NGK’s from AutoZone and it’s still misfiring, but not as bad. The original spark plugs that were in it before all of this was Acdelco Spark Plug 41-110. I did some research on them and it said that those weren’t even a fit for my vehicle, but they worked fine and there was no check engine light or misfiring when they were in the vehicle.

did you replace the wires also?
might be a good idea to hook up a scanner and see if you can see where the problem is occurring, (which cylinder specifically), then try swapping things around and see if the problem follows the wire or plug, etc
process of elimination....
p0300 is random, but that also just means it is happening on more than 1 at the same time, could be 1/4/7 so on so forth

 

[cmyoung2007]

did you replace the wires also?
might be a good idea to hook up a scanner and see if you can see where the problem is occurring, (which cylinder specifically), then try swapping things around and see if the problem follows the wire or plug, etc
process of elimination....
p0300 is random, but that also just means it is happening on more than 1 at the same time, could 1/4/7 so on so forth

Yes, I did. I have a foxwell NT809BT scanner, so if you or anybody has any experience with advanced scanners and can tell me what to use on it to find out what the problem could be, I’m all in for it. I’ll upload a screenshot of the misfires here in a little bit.

 

[Doubeleive]

Yes, I did. I have a foxwell NT809BT scanner, so if you or anybody has any experience with advanced scanners and can tell me what to use on it to find out what the problem could be, I’m all in for it.

not familiar with that scanner but they all basically do the same thing, you will want to select engine data, then it should have a misfire monitor or better to monitor live data view

 

[OR VietVet]

Welcome to the forum from Oregon.

You did not say which engine, why you were replacing the plugs and wires to begin with and you did not say which NGK plugs you installed. You did not say which plugs you replaced that you got online and where online. The AC Delco 41-110 is listed as original equipment. If the old ones were original and had never been changed, then they may have been correct plug from the factory. Since you said there was no misfire before this work, then I can only ASSUME that you were doing the work as a maintenance item and because of mileage. How many miles on the engine? If you did not crack the porcelain on the plugs during install and if the plugs you installed are correct for the unknown engine and unknown installed plugs and unknown wires and wires installed correctly and on right coil for correct plug and if use Dielectric grease, then you may have created your problems with something else done during the plugs and wires removal and replacement. What else did you MAYBE unplug or move? A lot of unknowns here. Are you sure the only code is P0300 and no other codes?

 

[Fless]

Use a scanner that can read individual cylinder misfires.

Spark plug torque is 132 INCH lbs (11 ft-lbs).

At what gap are the plugs set and did you have to adjust it before installing?

Make sure the plug wires snap into the coils and onto the plugs. Pop the hood in the dark to see if spark is getting outside of the secondary ignition system.

 

[cmyoung2007]

Welcome to the forum from Oregon.

You did not say which engine, why you were replacing the plugs and wires to begin with and you did not say which NGK plugs you installed. You did not say which plugs you replaced that you got online and where online. The AC Delco 41-110 is listed as original equipment. If the old ones were original and had never been changed, then they may have been correct plug from the factory. Since you said there was no misfire before this work, then I can only ASSUME that you were doing the work as a maintenance item and because of mileage. How many miles on the engine? If you did not crack the porcelain on the plugs during install and if the plugs you installed are correct for the unknown engine and unknown installed plugs and unknown wires and wires installed correctly and on right coil for correct plug and if use Dielectric grease, then you may have created your problems with something else done during the plugs and wires removal and replacement. What else did you MAYBE unplug or move? A lot of unknowns here. Are you sure the only code is P0300 and no other codes?

I apologize about that. I edited the post and included all the information of the vehicle. I was replacing the plugs and wires because they have never been replaced since the car was bought. The first ones were a-premium spark plugs and wires, and then I bought the NGK IX Iridium Spark Plugs 7397, and then the Duralast Silicone Spark Plug Wire Set 4713. There is no other codes at all.

 

[cmyoung2007]

Use a scanner that can read individual cylinder misfires.

Spark plug torque is 132 INCH lbs (11 ft-lbs).

At what gap are the plugs set and did you have to adjust it before installing?

Make sure the plug wires snap into the coils and onto the plugs. Pop the hood in the dark to see if spark is getting outside of the secondary ignition system.

I made sure the NGK Spark Plugs gap was set to 0.040 and they were straight out of the box.