Question about 2005 Chevrolet Cobalt
I have an 06 cobalt and the engine lightn is flashing and sounds like its not running on all cylinders and you can smell the gas that doesnt get burnt
It sounds like you have a misfire. Anytime a misfire is detected by the powertrain control module (PCM) it flashes the check engine light (CEL) on and off. Do not drive it this way because it won't take long to damage the catalytic converter. Have the diagnostic trouble code (DTC) read with a scan tool or "code reader" to see what DTC or DTCs are set. If it's a 4 cylinder, it will have a P0301 set for a cylinder # 1 misfire, a P0302 for a cyl # 2 misfire & so on. If the misfire is random (ocurring in multiple cylinders intermittently) it will have a P0300 set. Once you know which cylinder is misfiring you can check that cyl to see what the cause might be. It could be an ignition coil or spark plug failure. The # 1 cyl is always the one closest to the front of the eng or this car, the one closest to the passenger side fender.
Posted on Dec 16, 2008
This is a old question but is obviously still a common problem with the Cobalt. I had a '06 Cobalt with 2.2 liter engine start missing, check engine light flashing, underhood smelled of unburned fuel and vehicle was very down on power. I had AutoZone scan for codes but none registered on their machine. Here's how I proceeded:
Since there are only three components in this particular system I started with the cheapest and worked my way up. I replaced the spark plugs.. this gave me no change in operation.
This left the ignition coil and the igniter module. I bought both components but installed only the ignition coil while using the old igniter module. By replacing the ignition coil I completely resolved the misfire/rough running condition and the car returned to normal operation. I returned the igniter module to the store (unopened and unused) for a full refund.
Actual cost of failed component was $94 for the ignition coil set at a local parts store. The cost for spark plugs was a additional $28 but this was not the cause of the misfire. However, the engine has 100,000 miles on it and it is time for the plugs to be replaced and I did replace them with OEM Delco iridiums which cost considerably more than traditional plugs.
So check the ignition coil if you're having rough running and flashing CEL. It's a relatively inexpensive ($100) repair for the DIY'er.
Posted on Jan 13, 2011
There is so much it could be, we'll start at the free stuff you can try..... 1st ... are all the plug wires on ,and if so check to see if the plugs are tight. The unburned fuel may be causing the engine to come on from raw fuel in the exhaust..it may be a simple fix or it may be a more serious problem ..Let me know!
Posted on Dec 16, 2008
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