The check engine light for my 2006 Chevy Cobalt is on and is solid. I had it tested and the code was P0121. The car will run smoothly until you attempt to make a stop. The engine will run really hard and the RPMs will skip around. Sometimes the car will shut off or will continue to run. This will happen when you take your foot off the gas. Also car may cut off when attempting to make a right turn. It will restart without a problem.
You may have a faulty Idle Air Control Valve, with excessive carbon deposits this can cause your drivablity concern. They are fairly inexpensive and easy to replace. With you taking a corner this adds a load on the engine and can cause a stall.
〉 Answered on Nov 5th, 2014 by Amanda J. Pierce, MBA "AJ", Certified Mechanic, Project Coordinator; Primavera Scheduler at VIGOR Alaska Industrial Shipyard & BizzM3ch Solutions
The problem is most likely with your Throttle Position Sensor. It could have a short in the wiring. This determines the amount of gas going to the engine. I suggest you have a reliable shop check it out as a wiring/sensor problem can be difficult to locate.
〉 Answered on Nov 5th, 2014 by Gail Dunn, Owner at Women's Automotive Connection
That code is for a throttle position sensor which explains your symptoms. Sometimes cleaning out the throttle will take care of the problem.
〉 Answered on Nov 5th, 2014 by Gelina Aquilina, Service Advisor / Mechanic at