Hey, I have an 07 Cobalt SS/SC. Over the past couple months, I have noticed a small miss in the engine when I am in neutral. When it first started, it was soo slight that you would almost have to wait and try and feel it to even notice it. Anyways, over the past couple months it has gotten progressively worse. It is now at the point where my whole car will shake every few seconds, and it feels like it is going to stall out. My RPM's sometimes will fluctuate anywhere from 400 to 1500, at random times when in neutral. But this only happens every now and then. I have been reading up about the idle problem alot of people have been experiencing with this car. Soo I went and got my CEL checked, and it thru two different codes. P0130 ( car is running lean) and P0300 ( random misfire? I think ) . I am certainly not a mechanic, soo my friend helped me take out my throttle body and clean it up, with the proper air intake cleaner, i also changed the spark plugs. It did nothing! Did anybody here ever have a similar problem, or does anyone have any ideas as to what it could be? Thanks. Ohh and the car is bone stock except for an Injen Intake which was installed around two months ago. But the miss in the engine was going on long before that. Thanks for the help, i have been searching the forum for a while and cannot find an answer.

 

Forgot to mention, the car currently has 65000 kms on it, and has regular mobile 1 oil changes, and I use only 91 octane. Thanks

 

Wut mods do u have. Have u changed ure plugs yet. Take ure plugs out and look at them. Its still under warranty correct?

 

You<reading lol he already changed them. A vacuum leak could cause this, but would generally idle high. Hook a scanner up to it to isolate which cylinder the missfire is coming from could be a coil pack going bad

 

Yeah, a friend checked the vacuum lines, and the coils when he changed my plugs, also the computer says that the O2 sensor/s is/are working fine as well. And yes I still have power-train warranty. Thanks for taking the time to message.

 

I seen he replaced his plugs lol. I didnt put the whole sentence in i was meaning to say what plugs lol