Car Sputtering

chevrolet
cobalt

#1

My mother’s car has been having provlems. When it has been running for a little while stops and then it sputters like its going to quit and the after u give it the gas its fine for a while
What could cause this?


#2

Is the check engine light on? If it is go to an auto parts store and have them read the codes, post them here. They will look like P01234

You could have a clogged fuel filter, bad fuel pump, bad spark plugs, bad plug wires, failing crank shaft position sensor, any number of things.

Tell us more about the car, make, year, maintenance history etc.


#3

Fuel pump would be my first guess, but need more info.


#4

So the problem occurs when stopped at a stop light say, with a warm engine? But once you get going again it seems to run ok … hmm … well, when the engine is warm the computer injects less gas than when the engine is cold. So one idea, there either too much air or too little gas in the air/fuel mixture at warm idle. In other words the mixture is too lean. A problem like that could show up at idle but be swamped out by a more robust air and fuel flow and not show up at all when going faster. Some possibilities with the air & fuel systems are vacuum leak, fuel pressure too low, clogged injectors. Ignition system problems could cause this too. Spark plugs, spark plug wires, coils, ignition module, crank/cam position sensors, etc. It’s hard to say more with knowing about the engine computer’s diagnostic code status.

It’s also possible the idle rpm is too low for some reason. That would usually show up in the diagnostic codes.