Service engine soon light just came on. each time I push the accelarator, the engine sounds like it is "mis-firing" or "sputtering".

Use spark plug wire inductive flash tool to locate which cylinder is not firing. Check plug, wire, compression on that cylinder.

If the check engine light is on, you need to scan the computer for trouble codes next. The codes may direct you to the problem area.
You can research "GM trouble codes" online to get the procedure and the meaning of the codes you retrieve.

It sounds like your car has a misfire.When your cars computer sets a code for a mis fire the check engine light will flash then remain on steady.The smell is most likely a rich fuel mixture because of the misfire.

This sounds like a mass air flow sensor is malfunctioning. You should have a check engine light on. Or it should come on when it is hesitating. I would suggest taking it to Autozone and they will run diagnostics for free. And if it is the MAF sensor, then it will come up on their scanner.

SYMPTOM
The MIL is on, and DTC P1457 [leak detected in EVAP
control system (EVAP control canister system)] is set.
PROBABLE CAUSE
The EVAP bypass solenoid valve can fail due to
corrosion. Replace the bypass solenoid valve first. Clear DTC's and test drive.

sorry but,,if u have a miss fire in #3 ,,that's coil or wire or plug or injector,,,dont know y they replaced the battery or alt unless they were bad??? hope it helps

If your check engine light is blinking, you can take your car to Autozone, Advanced Auto or other parts house and ask them to get the engine codes. This ios a FREE service. It sounds like your camshaft positioning sensor, Cam Positioning sensor is bad. This is how comuterized systems tell where the cam and crackshaft are to set the timing. It sounds like you have timing issues.

Very common. Over time the O@ sensor builds up carbon from your exhaust which causes it to mis-read what the fuel air mixture is leaving the engine. This is a very common easily fixed problem.

ide need to know why he says its lean it could be a mis-fire or possibly and O2 sensor, dont drive if light is flashing could cause catalytic converter damage, i need to know the check engine light code is to further ***.

The flashing is telling you that the engine is mis-firing, the dealer will run a test to determine the cylinder that is mis-firing, chances are it is something simple