Hey guys,

Chev Cobalt SS 2006
59000 miles

so here is the problem, while driving on the interstate the car started having a serious misfire. we pulled in a autozone in order to get the codes pulled from the computer since the SES light was blinking.

The codes were a p0303 thats indicated a misfire in cylinder no 3.

We looked on the web and found a TSB that indicated that these models can have a harness rub and short to ground, however we preformed the procedure and no lines were damaged and shorted to ground.

We pulled the plugs and found our first clue at the problem.




As you can see the plug in no 3 cylinder was completely shot.

We replaced the plugs with champion 9001 iridiums. The plugs were shorter that the gm plugs witch is weird, but the clerch at the store assured us it was the correct plug for the model.

after replaceing the pugs and the no 3 coilpack the problem still persist. in fact we checked the sparks and all 4 coil provide spark to the plugs.

When we looked with a flashlight we could see that there was raw fuel in the cylinder no 3.

So what could be causeing a no combustion situation at this point?

 

Do a compression test.

 

sorry to hear what you are going through welcome to my world, Need to do a compression test when I did mine I had 0 psi in number 2

 

uhoh compression test. Im dreading this day.

 

maybe a bad injector if u can see fuel. switch the injector with another cylinder. should only take u 10-15 mins. pull the puel fump fuse and start the car first to let out to fuel press in the line

 

Let me see here never go with a champion plug in a gm #1 rule. Chrysler uses champ as there stock plug always go with ac delco/ ngkz or autolite which o sed them because that was my only option and I had alot of blow by issues. To me your problem is not compreeion but a fault leaky injector. And if a plug is shorter then the other one that is not the correct one. That would mean it would be easier to burn the plug. If you can't check the injector put the injector into another cylinder hole and see what happens. If it works injector is issue if the misfire comes with the injectr u moved from cylinder #3. If not it could be a possible bad computer. The only way I seeing -#3 compreeion bad and causing the plug not to burn the fuel is if you have no compression at all which your miles seems wierd I've seen it before but that's because the guy was not stock he was running a 2.6 pulley to much timing no meth and did run after run. His number 1 gave out. But look for the opvious. Another thing you could do is disconnnect your fuel injector harness and crank your car over so ure injectors can't send fuel. Because your plu could have went bad andcaused all the raw fuel to go into te cylinder. Put all the old plugs in while you do this so u don't burn them up. Crank over 10 second intervals and give 30 second breaks after . Check plugs for raw fuel if none make sure u put the newmplugs back in clean off all raw fuel from injector don't put the injector harness back together till u crank it over two more times. Put the injector harness back on and let it set with the key to the on position and then start the car. If this proceeds with te number 3 issue i say injector if you have done a compression. Test and it passed.

 

I had the same exact problem with f***kn NGK plugs dude the stupid previous owner put the wrong type plugs in it and cylinder # 3 got f'd up my spark plugs did the same **** except mine messed up the exhaust valves on that cylinder...PLEASE GO TO THE DEALER & PAY 40 $ & GET THE OEM SPARK PLUGS !!!!!! AGAIN DONT CHEAP OUT !!!!!!The Ones you have in the pics don't look oem for the ss coz they are TOOOOO LONG !!!!!

YOU LUCKED OUT Without any further damage....

HERE'S The Link To The DAMAGE On The Engine...I put a new engine and now parting out the old one !!!

https://www.cobaltss.net/forums/parts-66/cobalt-ss-sc-full-engine-lot-stock-parts-some-aftermarket-211981/

 

On ure third plug it seems the end of the plug is gone. When that happens it means kuboom so check compression first out of all ure other options

 

Did the compression test this morning and cylinder 3 shows no compression at all 0 PSI!!
I guess ill take it to the dealer monday to see if warranty is apllicable since i still have 1000 miles before it expires! And ill take yhe champion plugs back to advanced autoparts as zmany of you say its the wrong ones! Ill get u guys more feedback tomorow when ill know more

 

Cool if there is no oil on plug then I would say Cracked port on head or bent valve

 

Plugs are dirty but not oily...it might be the seal around the cylinder or around the plug itself...ill try to get more pictures

 

you aint got no compression coz that piece from the spark plugs damaged ur valves on that cylinder dude if the spark plugs that u had in there are oem put them back take it there otherwise they wont cover it just a headsup

 

Yeah I am saying bent valve. R u stock? No mods.....how much boost do u know your egts and afrs . I'm just wanting to know what's making people burn there plugs up lately

 

damn, i thought my stock plugs looked bad lol

 

damn, looks like u were running rich as ****!

 

it was completely stock...all gm parts...i only used 93 gas & GM declined coverage...but oh well i guess **** happens...

 

Yeah call a gm rep. customer service tell them whats going on with it. if it is still under warranty they have to legal contract unless they can find something that is not stock that could lead to the malfunction

 

dude lmao ur dumb

 

Actually i am not dumb. Very smart, im a like a 20 year old in 7th grade. But this is what i have came up with, stay witht he stock plug. or same mfg. But it is true. ford uses autolites and motocraft, acdelco is saturn and well all gm, imports usually use denso and ngk. Putting a bosch in a import like say my old supra yeah would not work. trust me.

 

so did you ever find the rest of spark plug #3 lol

dont stand for the stealership saying they wont cover it. call GM and tell them your problem.

 

oh yeah i know you have a shop i jsut see better results with the mfg type plugs

 

The lsj likes NGK copper plugs.

 

i just dropped the car at the dealership today and it took them the whole afternoon to figure out there was no compression in cylinder 3...i played i didnt know what the problem was, i put the old shot plugs back in and it seems they are going to cover all the work needed to be done with the car!! cant wait till tomorow to get GM approval on the work needed! ill get you guys the dealer's address if this slips through the crack! haha

the car is totally stock pushing a little over 60 kpa on the boost gauge..about 12-13 psi i think

 

Good gm better. U gotta push them dealer prices of crap. Alot of dealerships are great but u have those that are bullshit peices trying to save a dollar here and there. But congrats bro!!! I say valve and that'll be a easy job if the head is good. More then likly u will be getting a new engine. Just hope lol

 

well for me gm said that didnt wanna honor it, i called their support and they said they will pay for the labor only if i bought the parts from them which was like $ 5,000 so i was like f ya'll and took the car back....so i hope u get lucky man