Issues with 2010 Camaro SS misfiring after spark plug & spark plug wire replacement

[camguynj]

Originally Posted by PaulsSS

A sharp tech should be able to look at the wave forms and get a pretty good idea what is causing the issue. It doesn't have to be a dead miss to toss a misfire code. Like I said cracked spring or even a cracked piston ring-land etc could cause enough variation in the wave form to cause the code to be set. May drive fine, I been down this bumpy road a few times.

Good to know but wouldn’t a cracked spring or ring cause misfires and cel all the time? Also, what is the chance he cracked a spring or ring coincidentally when the dealer changed plugs? No way. Manipulation of a 13 year old 130k wiring harness mostly likely exposed a fault in the harness.

[PaulsSS]

Well not from changing plugs but running the engine hard enough and cold can cause cracked springs and ring lands. If a spring is cracked it may close the valve enough most of the time depending on how hot it is etc that the misfire code isn't set. Same with a cracked ring or land on a piston. Really depends how bad it is. There are other mechanical things that could play into this. Only reason I bring it up is I've seen some pretty crazy things come up when the obvious doesn't solve a code like this.

[Camarosmith]

I fired the car up today and it was running rough and idling rough, fuel smelling kind of rich.

I have examined the wiring harness and I'm not finding anything that looks to be an issue with it.

I put one of the old original square OEM coil packs on in place of cylinder 2 that was misfiring and still have the round Delphi coils on the other cylinders just as kind of an early test experiment

Fired the car back up and had what seemed to me to be the normal idle I was previously familiar with before all the issues, didn't seem to be running rough either and I didn't seem to get the rich fuel smell either.

I took the car around the block and it ran great with no stabilitrack light or check engine light on.

Before it was coming on pretty quickly, This doesn't mean I for sure resolved it though because it tends to come back just as soon as I think I have fixed it or take a 15 minute drive or a 30 minute highway drive or something however given that changing that coil pack seemed to improve the situation I feel I may be onto something there.

I'm gonna order all new OEM square Melco-Mitsubishi coils (12611424) like what originally came on the car from a legit source and install them. This may be the overall solution.

I'll have to drive the car more to see if it is actually resolved but I'm starting to feel a bit better about the situation.

I spent a lot of money changing the fuel pump that houses the fuel filter and fuel injectors which probably were not even the issue, I wasn't getting any codes related to them but still with the car being at 140,000 miles and those parts still being the original I suppose I'm money ahead. I started to theorize that this may explain the changing of misfires from cylinder 6 to cylinder 2

When I drove the car earlier it ran really good and sounds better than ever. It seems to have a lot more power too. It's all flooded out and raining so I can't get too crazy with it right now haha!

I had a 4th Gen V6 Camaro and after I replaced the spark plugs and spark plug wires the spark plug started arcing on one of the heat shields. I just took the heat shield off and that fixed that. I eventually had to replace coil packs on it as two of them failed over time I never did replace all three of them. The fuel pump did eventually fail on it at about 130,000 miles I hardly ever used premium fuel in it and I replaced it myself. And the hilarious part is I dropped the whole rear end doing it the hard way only to later find that the trap door had already been cut by someone who had the car before me I also could never get the damn floater that shows the fuel level in correctly when putting the fuel pump assembly down into the tank it would always get stuck down in the process. I remember trying to correct it a few times and just never did lol. The cars transmission eventually went out at 144,000 miles and I was gonna get it rebuilt but I bought the 5th gen instead and never did although I still love and miss that old 4th gen, great car!

[morepowerjoe]

Well here is my 2 cents. I wouldn't ever buy anything new from ebay because of all the scammers on there. My and my son occasionally buy a used mechanical part from there when needed but never an electrical component. I use amazon a lot because of the fact that they sell oem ac delco parts and have never had a problem with any of the tons of parts I bought from them. I don't remember if you said if you got new spark plug wires or not from the parts store but I would look at getting some high-quality wires from somewhere, there are tons of places out there for that. I recommend something like these
https://www.texas-speed.com/p-15865-...w-ls-cars.aspx I know sometimes the wiring harness on some of these older 5th gens get brittle with age and sometimes when they get moved around a lot they can cause issues. I would look into maybe replacing the engine harness if all else fails. And it's not that hard to take the valve covers off to check the springs just looks a little daunting but plan on replacing all the gaskets and bolt seals. Good luck sir hope you get her fixed.

[Camarosmith]

Great advice, Thanks everyone. Yeah I eventually had to change those gaskets on my 4th Gen around this time as well.

Yeah I got the new set of wires that is on the car now from Ebay, they came with the coil packs. I'm going to get some new OEM wires from a legit source as well.

I drove the car again just into town and back and had no issues with it. And lately it would regularly start to misfire just as I got into town with it and also startup with a misfire at times before I put the original coil pack back on cylinder 2 which it has not currently.

I still need to do a highway drive with cause previously I had it all like this and after putting the new wires on for a week and a half until I made a 30 mile highway drive it then started misfiring again and flashing the stabilitrack light again just before I got to my destination.

Or after the 30 - 45 minute drive it would make it without issues or start just about as I got to my destination, but also when it was really cold out and that car sat long enough to cool down after getting there in the really cold weather you would go to start it up to drive home it would start up misfiring usually until it got warm you could start it without it misfiring. I would at that point unplug the wire and plug it back on and then it would startup not misfiring and I would clear the codes and I would drive home without issues. I noticed it would most of the time but not always startup with a misfire when it was really cold also.

So far it's been good it passed my second drive test of a longer distance.

[pyroguy]

I'm glad to hear that putting the old cool pack on has seemed to fix the problem. I would definitely steer clear of the shops you took the car to trying to fix the problem without fixing anything. They totally screwed you over selling you parts and services that really weren't needed. Best of luck with the new coil packs when they arrive.

[Camarosmith]

I ordered the new OEM coil packs with the part # 12611424 from a website called www.gmpartsdirect.com they match the part number on the original stock ones I removed from the car and also look identical.

I'm wanting to get the OEM Spark Plug wires as well and I'm finding the gmpartdirect.com website currently has them on backorder

Another website https://www.gmpartsoutlet.net has them in stock and on all the other sites I search for the parts either by entering the make and model or my cars VIN are coming up is part #19351570 for the spark plug wire set & these are showing to be ACD# 748UU

Can anyone confirm that these are the stock OEM spark plug wires for the car?

I just wanna be sure I am getting the right spark plug wires for the car before I order them.

[Joe.G]

GM has a part Number and AcDelco will have another AcDelco is OE supplier for GM.

[morepowerjoe]

Yeah I would only go with the Ac Delco 748UU. They have them at Amazon and jegs in stock. But Joe G is correct.

[Camarosmith]

I ordered the 748UU set on Amazon for $74.33

thanks for confirming, much appreciated!

[Joe.G]

I worry about ordering stuff like this on Ebay and Amazon ( depending on actual seller ) something like this I would have ordered from summit racing.

[NOT A 45]

Originally Posted by Camarosmith

I fired the car up today and it was running rough and idling rough, fuel smelling kind of rich.

I have examined the wiring harness and I'm not finding anything that looks to be an issue with it.

I put one of the old original square OEM coil packs on in place of cylinder 2 that was misfiring and still have the round Delphi coils on the other cylinders just as kind of an early test experiment

Fired the car back up and had what seemed to me to be the normal idle I was previously familiar with before all the issues, didn't seem to be running rough either and I didn't seem to get the rich fuel smell either.

I took the car around the block and it ran great with no stabilitrack light or check engine light on.

Before it was coming on pretty quickly, This doesn't mean I for sure resolved it though because it tends to come back just as soon as I think I have fixed it or take a 15 minute drive or a 30 minute highway drive or something however given that changing that coil pack seemed to improve the situation I feel I may be onto something there.

I'm gonna order all new OEM square Melco-Mitsubishi coils (12611424) like what originally came on the car from a legit source and install them. This may be the overall solution.

I'll have to drive the car more to see if it is actually resolved but I'm starting to feel a bit better about the situation.

I spent a lot of money changing the fuel pump that houses the fuel filter and fuel injectors which probably were not even the issue, I wasn't getting any codes related to them but still with the car being at 140,000 miles and those parts still being the original I suppose I'm money ahead. I started to theorize that this may explain the changing of misfires from cylinder 6 to cylinder 2

When I drove the car earlier it ran really good and sounds better than ever. It seems to have a lot more power too. It's all flooded out and raining so I can't get too crazy with it right now haha!

I had a 4th Gen V6 Camaro and after I replaced the spark plugs and spark plug wires the spark plug started arcing on one of the heat shields. I just took the heat shield off and that fixed that. I eventually had to replace coil packs on it as two of them failed over time I never did replace all three of them. The fuel pump did eventually fail on it at about 130,000 miles I hardly ever used premium fuel in it and I replaced it myself. And the hilarious part is I dropped the whole rear end doing it the hard way only to later find that the trap door had already been cut by someone who had the car before me I also could never get the damn floater that shows the fuel level in correctly when putting the fuel pump assembly down into the tank it would always get stuck down in the process. I remember trying to correct it a few times and just never did lol. The cars transmission eventually went out at 144,000 miles and I was gonna get it rebuilt but I bought the 5th gen instead and never did although I still love and miss that old 4th gen, great car!

Doesn't it seem funny everytime you mess with the coils the problem seems to go away for a while? I suggest swapping all 4 coils from one bank to the other. Bracket and all. See if the misfire moves to the other side. If it does then replace the harness I was talking about. The wires in that harness partially break inside the insulation from vibration and you can't see it.

[HyperV117]

Other than the stablitrack message do you get anything else? I had an issue recently with my 2010 and it ended up being a bad ground. I added a thicker cable and car has been run great since.

[Camarosmith]

Ok so get this, now that I'm fairly sure that it was the old coil packs & cheap Ebay coil packs I replaced them with. Since I put the original used coil pack in place of 2nd cylindar and am still running the cheap round Delphi coils on the other cylinders until my all new OEM square Melco-Mitsubishi (12611424) coil packs arrive with no issues.

Although the issue seemed to improve also after the fuel pump was replaced along with all the fuel injectors by a local shop the problem still occurred although not as bad until I put the old original square coil pack on cylinder #2 now it's mostly gone

New coil packs will be here on the 10th or so

Anyways check this out. I was out driving probably the 3rd time with the car since the new fuel pump was installed in the car by the local shop. Drive to go get something to eat had about a quarter tank of gas and knew it, fuel level sensor was working when I got the car back from the shop, which was the first thing I looked for since I could never get the fuel level sensor to not be stuck down when attempting to replace the fuel pump myself on my 4th gen camaro.

So after the 3rd trip or so with the car, I notice on my way back from getting some lunch that all a sudden my car shows to be on empty when it had a quarter tank of gas just moments earlier. I pull over and fill the tank up knowing the sensor was more then likely encountered an issue.

Fill the tank up and still showed on empty.

I called the local shop that recently replaced the pump and let them know, They said no worries bring the car back to them and it's covered.

The small fortune I paid to have them replace the fuel pump came with a warranty on their work.

So I brought the car back for them to look at they had it overnight and call me today and said that they put another new fuel pump in the car and same issue the fuel level still showing on empty and the car has a full tank at this point.

So anything that you do or have done to this car just seems to open a huge can of worms that seems to be a mystery to just about everyone.

The shop was telling me that there is another fuel pump in this car a fuel transfer pump so the car actually has two fuel pumps.

So they say they are still working to resolve the problem, they seem to be fairly stumped. The only thing I mentioned is to check the fuel relay fuse also. Idk they are the experts, that's why I reminded them I took it to them.

Anything that is done to this car just opens up a whole can of worms that nobody can really seem to figure out though which is annoying. I'm at just under $3500 dollars so far on all of this madness

probably cost me another $1500 or so for replacing the SECONDARY Fuel transfer pump on the car or something so I can see how much fuel I have in the car again, nothing but a headache. I'm about to scrap this car at this point.

After looking into it myself and looking at the fuel tank unit, it does appear that to the right of the tank there is in fact an additional Fuel Gauge Tank Float Level Sending Unit part# 13592330 to the right of the fuel pump assembly module within the tank, stupid design why the need for two separate fuel level sensors if the pump assembly itself already has one? This design is ridicules as well as misleading so I'm assuming this Fuel Gauge Tank Float Level Sending Unit failed 3 days after the new OEM fuel pump assembly was replaced even though the fuel pump itself also has a fuel level sensor on it as well that was replaced with the pump. it appears this car has two of them, perhaps this is it, seems like it is, which is what the shop was telling me, we will see.

The local shop is going to have the car for another day till they identify the problem so I'll wait to see what they have determined tomorrow or so and provide an update.