69rrvert

I have a question about my Cobalt. The car is a '08 XFE Cobalt with 97,500 miles on it. All of the mileage is highway miles to work and back. I also run nothing but 89 octane fuel and Mobil 1 Synthetic since first oil change. Last month, the engine light came on with the P0300 code (#3 cyl. misfire). The dealer tells me the coil is shorted, replaces it, and sends me on my way. This past Tuesday, the light comes on again with the same code and this time it goes in the "engine pwr reduced" mode and is missing real bad. Take it back to the dealer yesterday and they tell me it is an old code and there are no new codes. they pull a bulleton and tell me that the valve is sticking and the fuel system, injectors, and throttle body need to be cleaned. They recommend me using a fuel additive until I can bring it in to be cleaned. I get the car back and today the light come on again and goes into reduced pwr again. I drive straight to the dealer with the car barely running and they pull the codes again. It has the same P0300 code, a throttle body code, and now a all cyl misfire code. Now I feel better because I felt it was a electrical problem the whole time. Then they proceed to tell me that the misfire is due to the fuel system and sticking valves. What are the odds in ALL of the valves sticking at one time? This is starting to smell a little fishy. Does anyone have any other ideas of what the real problem may be? I doubt all the valves will stick at the same time. Thanks for listening, Steven

kxrida2000

iTrader: (12)

p0300 is not number 3 cylinder its for a multiple cylinder misfire and it could be something as simple as spark plugs..throttle body eng pwr reduced usually means a bad throttle body also which is an easy fix so do it urself its a few bolts and a plug

69rrvert

I forgot to mention, they replaced the plugs last month also. It has the P0300 code, a code for the throttle body, and a code for the all cyl misfire. Thanks, Steven

nimble

I had a bad spark module when that code tripped on mine. It's got those heat sink fins located on top of the engine to the right. Don't drive around too long with a misfire cause you'll mess up the cat.

Maven

iTrader: (1)

most likely cause is actually a burned exhaust valve at this point with the work that has been done. relatively common. need to do a compression test. If it is its covered under powertrain warranty.