CEL- misfire on #3 cylinder

[Mongo RS]

Had Auto Zone scan the CEL, came back as a misfire on #3 cylinder. Is this just indicating I need a tune up (97000 miles on the clock) or is it an indication of a coil pack going bad? The car still seems to run fine and I cannot hear a miss.

[TooCool5]

I always try fuel injector cleaner first, most likely a plug or bad coil.

[Night trained]

swap coil and plug with another cylinder and clear code> then see what cylinder comes back misfiring.

[Ventmaster]

C'mon guys- nobody else thinks the first thing I'd do is put in some fresh plugs?

It's an easy job and time to do it. You could also swap the coil to another cylinder while you're at it.

[Nutbutt]

97k miles, I agree, time for some plugs. Also take a look through the throttle body a see if you are collecting oil. Could be time for an upper induction cleaning. Cylinder #3 is a classic indication of this on the v6s.

[Eddiefuzz]

I would have changed those plugs a while ago. The coil could have caused the misfire, but if the coil was bad the car would be running bad constantly. I've had many coils go bad and I keep a spare in my trunk for that reason. You can clear the code then swap the coil from 3 with one from a different cylinder and see if that cylinder misfires. When the coil goes, you'll know it, the car runs rough and you can shut it off and restart, the car will run fine for a few miles and it will start running rough again, the coil will need to be replaced. You can get individual coils on AMAZON for about $25, the dealer will charge $90. Good Luck with your car.

[Mongo RS]

Is it possible to reset the CEL without a code reader? AZ won't reset codes, and I haven't gotten around to getting an OBDII reader yet.

[JJPlace1]

Originally Posted by Ventmaster

C'mon guys- nobody else thinks the first thing I'd do is put in some fresh plugs?

It's an easy job and time to do it. You could also swap the coil to another cylinder while you're at it.

Time for plugs , the original AC Delco plugs work really good

[Nutbutt]

Originally Posted by Mongo RS

Is it possible to reset the CEL without a code reader? AZ won't reset codes, and I haven't gotten around to getting an OBDII reader yet.

Disconnect the battery.

[GM Parts House]

GM 3.6 with 97K would be absolutely 100% spark plugs. I would also change the Coil on that suspected cylinder. Most 3.6 Engines will only miss with a bad coil under load or when introduced to certain weather conditions.

I sent you over a PM to help you out.

Anyone else with 3.6 Issues, Please feel free to reach out to us at GM Parts House. My name is Chris and I know the 3.6 Inside and Out. We are a New Car GM Dealer and have access to any information that can help our customer's out.

Thank You!

[mpiersd]

I just had this happen yesterday. Cylinder #3 also.
I happened about 5 years ago just after I got the car and it had sat for a few weeks, at the time it had less than 6000 miles on it, now I'm right at about 65000.
I'm going to run some fuel injector cleaner through a couple tanks of fuel and change out the plugs and looking into possible upgraded coil packs.

[Elite Engineering]

At 97,000 miles your intake valves will be severely coked and that is one of the first symptoms along with hesitation off idle.

Take your intake manifold off, takes only 10 minutes tops and look at your valves directly and share some pictures.


This is what causes most misfires. Perform a manual valve cleaning (NEVER a engine running on a GDI engine!) and you will not believe its the same car when finished.

[Blueovalman]

I believe carbon build up and deposits on your intake valves are probably very thick being close to 100K miles. I would definitely take your Camaro to a automotive service shop or Chevrolet dealership service department you trust and have them do a complete decarb/fuel injection service on your 3.6L V6 engine and I would also run a bottle of Chevron fuel injector cleaner and/or Chevron fuel system cleaner through it as well. Your carbon build up/deposit level will depend a lot on if you used top tier brand gasoline’s,did your oil changes on time,and did all your other general maintenance on time. Your Camaro is overdue to replace your spark plugs and use AC Delco brand spark plugs. Also I would have all your ignition coils tested and replace your ignition coils as needed. Definitely replace the ignition coil on the suspected fouled cylinder/s. GM highly recommends only using “top tier” brand gasoline’s in all their models like gasoline brands like Chevron or Texaco gasoline with Techron etc.

[mpiersd]

Disconnected the battery and replaced the #3 coil and spark plug today.
CEL is gone, now we wait.