Q: My car had a rough idle, and if I sit at a red light or let the car run in idle for a few minutes my check engine light starts to

asked by on October 16, 2016

My car has a rough idle, and constant flashing CEL and service stabilitrak, and traction control light comes on, I had the code ran and it comes back as a misfire on cylinder 4, I was recommended by the auto zone clerk to change coil and plug. Plug was fouled, replaced coil and plug. No change.Any ideas of what it could be?

My car has 153000 miles.
My car has an automatic transmission.

Spark Plugs Replacement $113.11 - $716.47 Get a Quote
Fuel Injector Replacement $400.56 - $3968.30 Get a Quote
Car idle is rough Inspection $94.99 - $114.99 Get a Quote

A dead misfire on a single cylinder may be deeper than just a spark plug. If the compression for that cylinder is very low, the cylinder cannot fire. Low compression would be caused by worn piston rings. Also, if the fuel injector is leaking or not flowing enough fuel, this may cause a misfire as well if the injector is leaking bad enough. A fouled spark plug usually leads to a coil that is not functioning or lack of compression in that cylinder. If you would like to have this taken care of, a qualified professional from YourMechanic can come to your car’s location to diagnose the rough idle and help you move forward with repairs.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Brown stuff shooting out of radiator
You could either have air trapped in your cooling system, or you might have a bad head gasket. Based upon your description, I am leaning towards a bad head gasket. Testing the head gasket can be performed with a block...
Car fan doesn't work
It is very possible that your fan not working because your vehicle is running hot. After, the engine warms up, the fan is responsible for keeping the engine at proper temperature when it idles or while driving at lower speeds....
VVT (variable valve timing) Solenoid and Check Engine Light codes P0300 and P0011
Hi there. Through your research you probably discovered that there are multiple causes of a rough idle and the Check Engine Light beyond the VVT solenoid (https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-variable-valve-timing-vvt-solenoid). If you replace the second bank solenoid, it may improve your issue, but...
Car doesn't start - fast clicking noise. I attached portable battery / car "jumper" system. Clicking goes away but doesn't start
Hi there. When you jump start a car, the correct procedure is to attach the red line to the positive battery terminal and the black line to the negative battery terminal. This completes the electrical circuit. It is possible that...
How much labor costs is it to replace spark plugs and wires on a 2001 buick lesabre?
The cost depends on whether you have the V6 or V8 engine. The V8 requires significantly more time for the plugs and wires due to the amount of disassembly required to get to the wires, particularly on the right bank...
Camshaft position sensor
Hi There, The cost for a camshaft position sensor (https://www.yourmechanic.com/services/camshaft-position-sensor-replacement) replacement may vary slightly depending on the amount of time it takes to access the sensor. As you know, the camshaft position sensor is a magnetic sensor that monitors camshaft...
After changing a camshaft actuator, does one need to also change the spark plugs? Service writer recommended this but I decided ag
Hi there. If you haven't replaced the spark plugs on your vehicle yet, it's a good idea to have this completed around 75,000 miles. This is most likely why the service writer recommended the replacement.
My car is off, stuck in drive but the shift handle in park.
Hi Ana. Thanks for submitting your question today. It's quite possible that the gear shift lever may have broken, if the indicator is telling you the car is in "DRIVE" gear but it is pushed forward. As a safety device,...
I have a 2007 Cadillac STS , the passenger door will not unlock with the fob or unlock from inside the vehicle controls , you have
Hi Ken. Thanks for contacting us tonight. What you are describing is commonly caused by an open or damaged electrical relay that operates the power lock function on your door. When the relay is stuck in an open position, it...

Related articles

The Best Used Cars to Buy If You're a Personal Assistant
As As a personal assistant, you have a lot of demands placed on your time. Often it’s important that you be able to get around town quickly, running a ton of errands, picking things up here, dropping them off there,...
The Best Used Cars to Buy If You’re an Electrician
As As an electrician, you have to haul around wiring, tools and equipment, and tons of supplies. You can’t get by with a small used car, or even a big one. What you probably need is a good used cargo...
Essential Things to Know About the 2017 Chevrolet Bolt Electric Car
The 2017 Chevrolet Bolt is the first all-electric car under $50k. The Chevy Bolt has a higher EPA rating than Tesla and gets 238 miles per charge.