P0304 on 2012 Chevrolet Malibu

[SMB]

Hello all,

Need some help/insight/ideas/suggestions about this problem I am having. I'll try my best to be brief and to the point.

Engine is 2.4L 4 cylinders currently with 143K miles.
Latest oil analysis here: https://www.bobistheoilguy.com/foru...nknown-9-408-miles-2012-chevrolet-malibu

The issue is as follows:
I have been getting a CEL light for some time now. The code is P0304 Cylinder 4 misfire
the CEL goes away and then comes back intermitallnately.
Sometimes I can the SERVICE ECS & SERVICE TRACTION messages and only when the car is idling.
When I start driving, the SERVICE ECS & SERVICE TRACTION goes away.
Sometimes the CEL will flash along with these messages, BUT only while the car is in idle. Flashing CEL will either go away or stays on after I start driving.
While driving, car runs smooth and nice as if there is nothing wrong.

This is what I did so far and what i suspect the problem is:
1. Changed spark plugs
2. Switched ignition coils 1 & 4
3. Checked wires, connections and for vacuum leaks.
4. Did a compression test. The 1st result shows #4 making 90 PSI. When I added oil it went up to 120.
5. Few weeks after that I did another compression test and the the readings for #4 were jumping from 90 to 120 and than back to 90.

I suspect my piston rings are causing this issue. Now are they sticking or just worn I don't know how to tell.
Short of taking the engine apart, anything I can do?

Thanks in advance!

 

[dishdude]

If you have a miss, the vehicle will disable ECS and traction control.

 

[t1snwrbrdr12]

Need to do a leak down test. Also should compression check your other cylinders for comparisons sake.

 

[Oily_Thing]

A cylinder leakdown test might help you better identify what the problem is.

 

[slacktide_bitog]

What kind of driving conditions does your car see? You might need an Italian Tuneup

 

[nascarnation]

Originally Posted by t1snwrbrdr12
Need to do a leak down test. Also should compression check your other cylinders for comparisons sake.

THIS
I've seen some exhaust valve issues on these. The leakdown should help you identify if that's an issue. Then again if it runs reasonably well, you may want to just keep on trucking assuming there's no state inspection to deal with.

 

[SMB]

Originally Posted by dishdude
If you have a miss, the vehicle will disable ECS and traction control.

Yup. It will go away once I start driving. ECS never gave me any trouble so far.

Originally Posted by t1snwrbrdr12
Need to do a leak down test. Also should compression check your other cylinders for comparisons sake.

Yes I did a compression for all cylinders. #1 #2 #3 all have about 150 PSI

Originally Posted by slacktide_bitog
What kind of driving conditions does your car see? You might need an Italian Tuneup

75/25 City/Highway.

Originally Posted by nascarnation
Originally Posted by t1snwrbrdr12
Need to do a leak down test. Also should compression check your other cylinders for comparisons sake.

THIS
I've seen some exhaust valve issues on these. The leakdown should help you identify if that's an issue. Then again if it runs reasonably well, you may want to just keep on trucking assuming there's no state inspection to deal with.


Yeah that is the plan. Still starts and runs fine as if there is nothing wrong. No state inspection here in FL.

 

[benjy]

good luck! girlfriend dumped her oil burning qt on a thou 13 2.5 after other issues + off + on engine check lights. try the malibu forums as many have issues!!

 

[tahoe_hybrid]

Originally Posted by SMB
Hello all,

Need some help/insight/ideas/suggestions about this problem I am having. I'll try my best to be brief and to the point.

Engine is 2.4L 4 cylinders currently with 143K miles.
Latest oil analysis here: https://www.bobistheoilguy.com/foru...nknown-9-408-miles-2012-chevrolet-malibu


Thanks in advance!

what was the OCI when it did work?

 

[tahoe_hybrid]

Originally Posted by SMB
Hello all,

Need some help/insight/ideas/suggestions about this problem I am having. I'll try my best to be brief and to the point.

Engine is 2.4L 4 cylinders currently with 143K miles.
Latest oil analysis here: https://www.bobistheoilguy.com/foru...nknown-9-408-miles-2012-chevrolet-malibu


Thanks in advance!

what was the OCI when it did work? since you bought it at 129 i think you got screwed the OCI must have been high

 

[Trav]

Originally Posted by SMB

5. Few weeks after that I did another compression test and the the readings for #4 were jumping from 90 to 120 and than back to 90.

I suspect my piston rings are causing this issue. Now are they sticking or just worn I don't know how to tell.
Short of taking the engine apart, anything I can do?

Thanks in advance!


+1 on the leak down test but you can do a few small things you can do at home before getting deeper into it. The fact the cylinder is building compression suggest the valves are not burned or damaged to the point it wont make compression but the cylinder is loosing it right away.
A sticking valve can also cause this as could sticking rings.

What I would do first is run a can of top engine cleaner slowly through a vacuum line, there are lot of decent one out there from GM,Chryler, Subaru, Toyota, etc, any should do the trick if there is a valve hanging. Use it and let the engine sit a couple of hours before starting.

Once that is done remove the plugs and put 2-3oz down each plug hole, being an inline engine this will find its way around the whole circumference of the rings and let that sit overnight.
Get the engine started so it idles smoothly turn it off and add 1 can of Berrymans Chemtool to the oil and idle for 15-20 min, DO NOT rev the engine or move the car during this operation, idle only.

Change the oil and filter and add 1 bottle of Rislone high mileage concentrate to the oil and a full bottle or Redline SI-1 to a full tank of fuel, drive it a few hundred miles normally and check the compression again, if its still low you need to get deeper into it.

This is a DIY shade tree job but it may just produce some good results for little time and money.