P0300 + P0204 Misfire no spark on passenger side 8-6-4-2

[Geotrash]

Whenever you get it all fixed, you'll have to clear out ALL the codes...
The stabiltrack, etc codes come on when there are hard misfires.. this is normal
So make sure you get all the codes cleared so you are not chasing ghosts that don't
really exist

100%. I forgot to mention that. Thank you, @Foggy

 

[jared999]

Hundred bucks says you clean up that ground and you won't need to take it into a shop.

Is this the ground you are referring to?

 

[jared999]

Whenever you get it all fixed, you'll have to clear out ALL the codes...
The stabiltrack, etc codes come on when there are hard misfires.. this is normal
So make sure you get all the codes cleared so you are not chasing ghosts that don't
really exist

Thanks I will be happy to do that when its fixed

 

[Foggy]

I'm pretty sure there is a ground on the drivers side at the rear of the cylinder head too..
Check it as well. I've also heard of the injector and coil (left and right) harnesses going
bad internally... And there is a replacement that gm makes

 

[Geotrash]

Is this the ground you are referring to?

View attachment 404950

Yes, that’s the one! And as Foggy says there’s one at the back as well, but the front one is the one that suffers from corrosion the most due to exposure to the elements coming through the grille.

 

[jared999]

Yes, that’s the one! And as Foggy says there’s one at the back as well, but the front one is the one that suffers from corrosion the most due to exposure to the elements coming through the grille.

OK Thanks. I'm going to get my wirebrush and clean it off very well and then inspect the back one too.

 

[jared999]

In my opinion, you have a problem with either the ground or the power supply wire to the passenger side bank of ignition coils. We see this from time to time and it's almost always a poor ground as previously stated, a short in the wiring harness serving that bank's ignition coils (look for chafing of the loom), or a loose/corroded pin in the connector for that bank of coils.


Yes, passenger side.

The ground connections looked OK. I still took them off and wire brushed them thoroughly which didn't solve the problem. I tested at the ground bolt, I'm getting 12-12.3v at both. I assume if that is the case, that means the ground wiring going to those points is OK.

If I can find one connector for that whole bank (which would then branch off to 4 coil connectors) I will test that connector. Otherwise I will test at one of the connectors (there are two) at the ECM. I will slowly go down the check list (you mentioned 4 areas to look).

 

[j91z28d1]

incase I missed it, what year is it?

and what are you trying to do again? power at the coil plugs? I believe they have keyed 12v and the ecm fires the coils with a switched ground. if you have power and want to check at the ecm pin to coil pack pin for continuity, I can probably pull up the pin out for your truck?


edit. I forget these arw 4 wire coils.. so there's keyed 12v and neg. then one wire that connects to all 4 to the ecm, and one to the ecm to fire it.

 

[j91z28d1]

 

[Fless]

incase I missed it, what year is it?

and what are you trying to do again? power at the coil plugs? I believe they have keyed 12v and the ecm fires the coils with a switched ground. if you have power and want to check at the ecm pin to coil pack pin for continuity, I can probably pull up the pin out for your truck?


edit. I forget these arw 4 wire coils.. so there's keyed 12v and neg. then one wire that connects to all 4 to the ecm, and one to the ecm to fire it.

In the signature...