hesitation problem on 2005 Chevrolet Cobalt

when stopped at a light the idle spped seems to drop and the engine starts hesitating like it is getting ready to stall. If I give it a little gas to bring up the idle RMPs it seems to stop hesitating. I have replaced the knock sensor but it has not resolved the problem. Any suggestions? I live alone and can't afford the dealer costs. My sons work on my car.

by in Dayton, OH on March 22, 2010
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5 answers 5 comments
ANSWER by , June 29, 2010
I had the same problem. I bought a bottle of fuel injector cleaner and it runs perfectly now.
COMMENT by , December 20, 2010
You need to clean the carberator and replace fuel filter because water may have froze inside of it. A normal issue.
COMMENT by , April 06, 2011
lol ....tried didn't help
ANSWER by , September 20, 2012
buy some mass air flow sensor cleaner and spray the mac sensor down then grab some throttle body cleaner and spray all the dust/oil/dirt/carbon off of the inside of the throttle body, worked for me car idles at 900 rpm and dosnt bounce around or stall
ANSWER by , March 22, 2010
is the check engine light on? How many miles are on the car? Ever replace the fuel filter or air filter? You can also tell one of your sons to take a rag and with some carburator cleaner, take the air snorkel off the throttle body and clean the interior of the throttle body, even spraying the cleaner into the throttle bore and rubbing the interior with the rag.
COMMENT by , September 29, 2010
the check engine lite is on. The car has 75,000 on it. Checked the air filter and it is clean. did not check the fuel filter/ Cleaned the throttle body. Still idles rough and the temp goes up to 190 to 200 pretty quick.
COMMENT by , April 06, 2011
My 2005 cobalt just recently had the engine light come on and wanted to stall at stops....had a tune up, then engine light came bk on...had light checked it said mass air flow sensor....same thing...checked light it said the lower sensor...had it replaced...same thing...wanted to stall ...had the fuel filter changed....same thing...took it to mechanic again and he thinks it's the ignition coil and they're looking for a cheap one or at the salvage yard...this was all in a matter of 5 days
ANSWER by , June 24, 2010
Check the Spark Plugs
ANSWER by , April 06, 2011
try ignition coil
COMMENT by , December 07, 2011
Yes, my 2007 also had the same problem and it seems to be the ignition coil, it costs about $90 to replace without labor