Engine ticking, clicking sound while gas is pressed

IMARINE

MEMBER
2010 CHEVROLET COBALT
49,300 MILES

I have taking very good care of my car since I got it. There is nothing wrong whatsoever except for this sound the engine makes when I press of the gas. It seemed to start after I put in performance headers. It doesn't affect my HP but my gas miliage is really bad. I'm getting around 16.5 when I should be getting 24. I was told it may be the valves, I think it has something to do with the fuel injection system. My car doesn't overheat and there isn't any knocking sound. Just an audible clicking while the acceleration is pressed.

1 Reply

CARADIODOC

MECHANIC
33,864 POSTS

Given the multiple systems it is almost certain you're hearing an exhaust leak. That will sound like a ticking noise. In between the puffs of exhaust gas flow the momentum can create puffs of vacuum that draw in outside air. The front oxygen sensors detect the unburned oxygen in that air and report it as a lean condition. The Engine Computer responds by commanding more fuel. Since you don't have extra air coming into the engine, that additional fuel doesn't burn. It goes out the exhaust pipe, wasted. No matter how much extra fuel the computer requests, the oxygen sensors will keep on seeing that unburned oxygen that is sneaking in and the computer will keep on adding more and more fuel.