2009 Aveo cylinder misfire diagnosis

[avguy]

No recall for coil pack ...

http://www.aveoforum.com/forum/f81/r...9-aveos-13419/

[Drake314]

http://www.aveoforum.com/forum/f81/r...9-aveos-13419/

Thanks for the info, I would have thought that the government website I checked would have given me info on this recall. Well I called the local Chevrolet dealer and they told me they had done the work on the car for the recall back in May 2012 so it has been done on it already. That takes that option off the table, now I am back to needing to find out if the ignition coil pack is good or not and how to test it.
I did read through the thread you posted and noticed the info on the recall stated a spark plug number and a new gap measurement of 0.031-0.035 inch. I wonder if this could be making an impact on the car since I gapped the plugs around .41 due to the original specs calling for 0.039-0.043 inch gap? Still I am wondering why it only throws the same code of P0304 that affects only that cylinder.
Thanks again for all the input.

[Drake314]

Problem fixed. Just wanted to give an update that might help someone down the line with the same problem I was having. I did a compression test with a compression test gauge I bought from Amazon for about $24 dollars. Took all spark plugs out, disconnected fuel pump relay in the fuse box, and with the accelerator pressed all the way down I cranked the car with the compression gauge installed in each spark plug well until the needle stopped moving. All came back with 170 psi so I figured the problem was not being caused by a head gasket/valves/pistons or the like. Decided to take a chance and I bought the coil pack from Rockauto.com for about $80. Installed the part and lo and behold the car started running smoothly. Cleared the code and test drove it and problem fixed! Check engine did not come back on and drives like a champ. So glad it wasn't anything more serious or expensive although it is weird that at 80k miles the coil pack would go back. Could have had something to do with the coolant hose bursting, but either way hope this helps anyone having similar issues.

[avguy]

.... it is weird that at 80k miles the coil pack would go ....

If Chevy replaced the coil pack for the recall in 2012, that would make the mileage on the replacement pack much lower than 80K. But perhaps they didn't do the work they were supposed to, which wouldn't be the first time that ever happened. And that would explain the part failing because it (i.e the original pack) was well known to be defective. You might be able to find that out based on the part # of the coil pack you removed. In any case, glad to read it's fixed, and thanks for posting the outcome!