2008 tahoe p0306 issue

[Nickct203]

I have a 2008 tahoe ltz 5.3. My wife was driving yesterday and all good until she came to a red light. The service stabilitrak, Trac control off and the check engine light all came on. Well the CEL was flashing then went steady. She said it had a real rough idle and could barley drive. I got home from work put my scanner on it and got a P0306, cylinder 6 misfire. I changed the plugs and wires cause it needed it regardless, and still no good. Swapped the coil packs with cylinder 6 and cylinder 1, still no good. You can hear that freaking cylinder 6 rapping away. Does anyone have any idea what else? I did notice that when I went to the pass side to change the plugs and wires I smelt an over abundance of gas. Could it be that the injector went bad? I also notoce that after doing the work all the lights, specially the inside lights were pulsating. My wife said its been doing that but not as bad as it was now. Could a bad alternator or the voltage regulator in the alternator be bad and cause all my issues?

 

[Geotrash]

How many miles? The stabilitrak and traction control system will shut off and trigger the warning if the engine isn't running right and is throwing codes. But when you say you can hear cylinder 6 rapping away, can you elaborate a bit more please? Is it a loud knocking or tapping noise? If so, you likely have a failed AFM lifter. #6 is an AFM cylinder.

Pulsating lights could be caused by the uneven idle that's accompanying the problem, or it could be a separate issue, such as a failing alternator as you suggest. But that would not be the cause of the misfire.

 

[Big Mama]

Never hurts to check all of your ground cables too.

 

[02Z71Raven]

Injectors aren't too difficult to swap either. Check to make sure the connectors are clean and no signs of corrosion.

I did all these things and then sent it to the shop and found a collapsed lifter had worn into the cam. I hope you have better luck.

 

[swathdiver]

I have a 2008 tahoe ltz 5.3. My wife was driving yesterday and all good until she came to a red light. The service stabilitrak, Trac control off and the check engine light all came on. Well the CEL was flashing then went steady. She said it had a real rough idle and could barley drive. I got home from work put my scanner on it and got a P0306, cylinder 6 misfire. I changed the plugs and wires cause it needed it regardless, and still no good. Swapped the coil packs with cylinder 6 and cylinder 1, still no good. You can hear that freaking cylinder 6 rapping away. Does anyone have any idea what else? I did notice that when I went to the pass side to change the plugs and wires I smelt an over abundance of gas. Could it be that the injector went bad? I also notoce that after doing the work all the lights, specially the inside lights were pulsating. My wife said its been doing that but not as bad as it was now. Could a bad alternator or the voltage regulator in the alternator be bad and cause all my issues?

Pull the rocker cover and see if it's a busted spring, rocker, collapsed lifter, bent pushrod, etc.

 

[iamdub]

I have a 2008 tahoe ltz 5.3. My wife was driving yesterday and all good until she came to a red light. The service stabilitrak, Trac control off and the check engine light all came on. Well the CEL was flashing then went steady. She said it had a real rough idle and could barley drive. I got home from work put my scanner on it and got a P0306, cylinder 6 misfire. I changed the plugs and wires cause it needed it regardless, and still no good. Swapped the coil packs with cylinder 6 and cylinder 1, still no good. You can hear that freaking cylinder 6 rapping away. Does anyone have any idea what else? I did notice that when I went to the pass side to change the plugs and wires I smelt an over abundance of gas. Could it be that the injector went bad? I also notoce that after doing the work all the lights, specially the inside lights were pulsating. My wife said its been doing that but not as bad as it was now. Could a bad alternator or the voltage regulator in the alternator be bad and cause all my issues?

As @swathdiver said- Check under that passenger side rocker cover.