Cylinder 1 Misfire, please help

[jan_mast]

Mechanics,

I have a 2008 Chevy Cobalt that i have been having an issue with.

I have been having a misfire in #1 cylinder for awhile now. I bought a code reader after the check engine light came on. The error code is P0301.

I first replaced all of the spark plugs. Still had the misfire. So i ordered and replaced the coil pack for the #1 cylinder. (I am assuming that the #1 cylinder is on the left if i am standing in front of and facing the vehicle).

So i am a little unsure of how to proceed to fix this misfire issue. Any help would be GREATLY appreciated. Thanks!

 

[YelloEye]

You are correct, cylinder 1 is the one closest to the passenger fender.

What motor do you have? When are you seeing the misfires happening? What's your spark plug gap set at?

 

[Bass_Waves]

Coil pack is easy to replace. Mainly like Yelloeye asked. Plug gap.
Also I would check the wiring to the coil pack.
If a new coil pack does not fix it. Wiring is good. Report back.

 

[YelloEye]

Play musical coil packs, then you don't unnecessarily buy one.

 

[Bass_Waves]

Quite funny but I have 4 extra lsj coil packs in case of emergency lol

 

[YelloEye]

Meh, pack goes I'll run around all Subaru till I get a new one

 

[jan_mast]

I have already replaced the coil pack for the #1 cylinder, no joy.

I bought the plugs that were already gapped. Plus I replaced all four and only #1 cylinder is misfiring. I'll have to look up what the engine size is.

I tried looking up the wiring but was unable to find part number for it. Any ideas? Thanks again!

 

[Bass_Waves]

No no as in check for any cut wiring. The connector to the coil pack and such.
Do you know what type of cobalt you own.?
Cobalt LT
Cobalt LS
Cobalt Sport
Cobalt SS
Since its an 08 it can be any of those.

 

[jan_mast]

I have an LS (2.2L)

I will follow out the cable, and check the connector, for the #1 cylinder.

 

[Bass_Waves]

I think somebody has extra engine parts here. Silver Balt?

 

[YelloEye]

When are you getting misfires?

 

[jan_mast]

I did inspect the cable, nothing obviously broken.

Is there a method to test the cable? I am an electronics technician by trade, just don't have the pin out if the cable. Nor do I know what the voltage should be when that cylinder fires. Thanks for all the help thus far!

 

[YelloEye]

You should be able to compare the input of the other 3 as a reference against the bad one.

Here's the connector info.

 

[jan_mast]

Thank you. I will look at this tomorrow. It's late here in Guam.

 

[jan_mast]

I pulled off the plug for the #2 cylinder and took readings on those pins and then took readings on the plug for #1 cylinder and they were virtually identical. It doesnt seem to me like its an electrical problem...

 

[Bass_Waves]

This would be my last option. Only because timing is probably OK since all other 3 are fine.

I would say there may be a missfire caused by valves. Highly doubt it. It can be anything really. But I'm dead set something is not closing right. Pull the valve cover off. Check #1 and see if valve springs aren't broken.

Another thing could be piston rings. Never know.

Wait for more input . That is just me thinking too mucj

 

[YelloEye]

Valve seats might be toast

 

[Chopper8176]

I have the same problem, my first thought was the fuel injector. I first got code p1174 (fuel/air mixture imbalance), I found my purge valve was stuck shut, I got it to start purge breathing again. My CEL shut off, but came back on a few days later. I checked code reader and it came up with p0301. Just wondering if you found out your car's problem?

 

[bockwoldt]

In cases of misfires these are main steps to follow:

Move spark plug from another cylinder not having the misfire. If the misfire follows the cylinder, change the spark plugs. If the spark plug is good, then change the coli pack from another known good cylinder. If misfire follows, change the coil pack. If this doesn't work, move a known good injector from another cylinder. If misfire follows the injector then replace.

There are also a set of o-rings around the fuel injector and collar. If the above does not work, take some carburetor cleaner and spray around the injector while running. You will here a sucking noise and engine RMP increase if it's bad. Replace the o-rings if this is the case.

It's a matter of deduction with a cylinder misfire. You also don't have to spend a lot of money replacing plugs, coil packs and injectors. Move the pieces from the known good cylinders to see if the problem follows.

This recently happened on my 2008 LT on cylinder 4. I went thru the steps above and still had the problem on cylinder 4. Once I sprayed the carb cleaner around injector 4, I heard the sucking of the fluid and RPM kick up briefly. Replaced the o-rings and all is well.

 

[papa karl]

Hope you don't have what my Mazda had, a stuck open valve!! Try a compression test, but I hope it's a bad injector