Missfire P0300 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Olov · 10-05-2022, 09:01 AM

I still have big problem.. 2015 SS about 55k miles, got misfire and have checked that I have ground to all coils, have signal from ECM to all coils, have spark on all plugs, I have signal from ECM to all injectors, I have power from fuse to all injectors, no bent pushrod, I have "stripped" all cables around the engine and it all looks good..
missfire on 2 and 4.. BUT.. there was a strange thing, when we were trying to find anything, we by misstake damages one groundcable that fits on the backside of the head.. there is on on the right side and one on the left.. the one on the left goes direct to the coils but the one on the right side (the one we took loose) goes together with many other cables ..
The strange thing is that when that groundcable was lose I hade missfire on 2 and 4 and when we did hold it against ground the missfire moved to 4 and 6 ???.. I did fix that cable and bolted it back to the back off the head.. and now I have missfire on 4 and 6
I think it has to be some fuel problem, as I have spark.. and the sparkplug is not wet...
anyone that has a good idea??

0stones0 · 10-05-2022, 09:38 AM

Checking fuel pressure would be reasonable.

Olov · 10-06-2022, 03:45 AM

no problem with fuel pressure... :( have lifted the heads off.. no problem there that i can se... sending the heads for checkup...

ElderJ · 10-06-2022, 10:06 AM

Did you do a compression check? I'm not a mechanic, but I've seen several guys get misfires due to low compression in a cylinder.

10-05-2022, 09:01 AM	#1
Olov Drives: Camaro 2SS RS 2015 Join Date: Sep 2022 Location: Sweden Posts: 2	Missfire P0300 I still have big problem.. 2015 SS about 55k miles, got misfire and have checked that I have ground to all coils, have signal from ECM to all coils, have spark on all plugs, I have signal from ECM to all injectors, I have power from fuse to all injectors, no bent pushrod, I have "stripped" all cables around the engine and it all looks good.. missfire on 2 and 4.. BUT.. there was a strange thing, when we were trying to find anything, we by misstake damages one groundcable that fits on the backside of the head.. there is on on the right side and one on the left.. the one on the left goes direct to the coils but the one on the right side (the one we took loose) goes together with many other cables .. The strange thing is that when that groundcable was lose I hade missfire on 2 and 4 and when we did hold it against ground the missfire moved to 4 and 6 ???.. I did fix that cable and bolted it back to the back off the head.. and now I have missfire on 4 and 6 I think it has to be some fuel problem, as I have spark.. and the sparkplug is not wet... anyone that has a good idea??

10-05-2022, 09:38 AM	#2
0stones0 It don’t come easy. Drives: 2010 2SS RS M6 Join Date: May 2014 Location: WI Posts: 2,591 View My Garage	Checking fuel pressure would be reasonable. __________________

10-06-2022, 03:45 AM	#3
Olov Drives: Camaro 2SS RS 2015 Join Date: Sep 2022 Location: Sweden Posts: 2	no problem with fuel pressure... :( have lifted the heads off.. no problem there that i can se... sending the heads for checkup...

10-06-2022, 10:06 AM	#4
ElderJ Drives: 2014 Camaro 1LT Join Date: Aug 2019 Location: Central Florida Posts: 372	Did you do a compression check? I'm not a mechanic, but I've seen several guys get misfires due to low compression in a cylinder.