Q: #3 Misfire engine light

asked by on

My Hummer is running fine, but the service engine light comes on and then off. The service engine code appears showing #3 Misfire. I have brought my car to several dealerships and the mechanics state there is only the #3 misfire. Is this possibly an electrical problem?

Yes, it can be an electrical issue. A misfire at a particular cylinder can be caused by ignition, fuel injection, mechanical issue, or vacuum leak. I’m curious why none of the dealership techs repaired it. Faulty sparks plugs, coils, or electrical connections can all cause this. So can a fuel injector or vacuum leak close to #3 cylinder. A leaking head gasket at #3 would also cause a misfire. Have a certified technician from YourMechanic inspect the misfiring issue and determine what fixes are needed.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 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
  1. Home
  2. Questions
  3. #3 Misfire engine light

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: MAP sensor

Hello. MAP stands for manifold absolute pressure. So the answer to your question would be that it is the manifold absolute pressure sensor that there is something wrong with. The map sensor reads the pressure in the manifold and sends...

Q: Changing spark plugs in the back of the engine

It all depends on the engine of course. A lot of the Chrysler V6's, a lot of Toyota V6's--you've got to pull the intake manifold off and there is no other way. Since the plugs can't come out, they hit...

Q: Unable to start after it rains or misfires until the engine heats up in high moisture conditions

Hey there. This misfire no-start in wet or damp weather is going to be caused by the ignition system of the engine. In order to isolate the cause you can remove the inside engine cover and then start the van....

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
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.