Skip the auto shop - Our mechanics make house calls

Q: Getting code P0303

asked by on

I am getting a code P0303, which is for a cylinder 3 misfire. I am not sure, but I may need a coil replaced.

A: If you have already taken the first step of...

If you have already taken the first step of getting your codes scanned, the next thing to do would be to have an ignition test performed by a qualified technician. Attempting to do this yourself could result in being shocked by high voltage. This test would entail removing the ignition coil and placing the ignition tester in the circuit between the coil and the spark plug. If the spark plug or coil is faulty, the light will not flash consistently or at all on the ignition tester leading the technician to believe that either the coil or the plug is faulty for cylinder three. After confirming the lack of spark to cylinder three, the technician may erase your fault codes and switch your number three coil to the cylinder adjacent to it. When your Check Engine Light comes back on, if the misfire has switched to the other cylinder, the coil is faulty. If the misfire stays on cylinder three, the spark plug is faulty. If the spark plug is faulty, it is a good idea to have all spark plugs replaced at once.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
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

Get a quote

What others are asking

Q: My vehicle is shaking when I drive past 50 mph

Hi there. From the description you have given, the drivability problem your vehicle has may be a fuel delivery problem. This would account for your vehicle not wanting to start that one day. Next day, you were entering the highway...

Q: sub woofer popping in-out

Your issue sounds to me like a loose connection. I would recommend having your power, ground, and RCA wires checked to make sure they are connected properly and that no loose connectors exist. If the subwoofer itself were faulty it...

Q: The bushings are pressed in the control arms

The repair is intensive and requires several special tools. In this case, it appears that the control arms will have to be removed and replaced. The repair will improve your stability and tire wear. A qualified technician, such as one...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.