Oily chevy cobalt question

[willsmysticcobra]

Hey all , my mother has an old company car she drives in the winter and she brought it to me with a CEL for P0030-02,PO300, and U0101. So basically upstream O2, random engine misfire , and lost communication with trans control module.

Car is an 06 with the 2.2l and has 109k on it with stock plugs. Picked up a set of those and figured I'd swap those in hopes I'd clear the PO300 misfire code. I'd check all connections/ grounds for that TCM code that is common on these cars and order an AC Delco O2 sensor off Rockauto.

So I pulled all the plastic cover shit off and found significant oil stains on the valve cover.

I inspected the plastic intake cover that connects to the t-body and found a really corroded rubber pvc hose ...

Now I'm satisfied I found the leak but was a bit alarmed when I pulled plug 3 and found out how oily it was

I am now guessing the CEL for the misfire was for the split PVC hose but would the oily plugs be fixed by replacing the valve cover gasket ? I just want to figure out why the plugs were oily ( mostly #3 in the pic ) .

I appreciate it !

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[10sec]

95% of the time when one of those cars has a misfire it's the stupid ignition coils, replace those and you're good.

I wouldn't worry about an oily plug TBH, I'd be more worried about that stupid transmission code that those cars commonly have.

 

[DEEZUZ]

My God how clean those fingers are.

 

[CHI2000GTP]

I had the same problem in our '07 Corolla. Oil was pooling in the spark plug wells. I looked it up and found out the valve covers gasket needed replacing. The old gasket was so hard and brittle it had split in 3 places. Bought the Felpro set and done. Both the Cobalt and Corolla engines are 4 banger DOHC engine, so I imagine its the VC gaskets in your case as well.

 

[willsmysticcobra]

My thought as well !