Skip the auto shop - Our mechanics make house calls

Q: Engine misfiring 2003 Honda CR-V

asked by on

Plugged in OBDII. Got codes for misfiring on cylinders 1,2, and 3 as well as a random misfire code. Also bank 1 oxygen sensor code and P0420 catalyst below efficiency (I've had that last code for awhile and the code comes and goes). What is causing the misfires?

My car has 270000 miles.
My car has an automatic transmission.

Misfires can be caused by several things. I would first check for vacuum leaks, then I would pull the plugs to see if they need replacing. It is possible that have a fuel system concern, but I would lean more towards a vacuum leak. The amount of air the engine intakes, is measured to ensure that the proper amount of fuel is delivered. If there is a vacuum leak, extra air that the engine is not expecting enters and causes the air/fuel mixture to be wrong causing a misfire. If you need help pinpointing the problem, a certified technician, like one from YourMechanic, will be able to diagnose the misfiring issue and help you move forward with repairs.

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: P0420 code and engine is not starting.

Hi there. The p0420 code means that the catalytic converter is below threshold and is not functioning correctly. This code comes up when the catalytic converter can no longer burn off any fuel in the exhaust system. Take a raytech...

Q: Car making a hard knocking sound

It sounds like you have a broken engine or transmission mount, causing your engine to move. You could also have an engine misfire. An inspection of your engine's knocking sound from a qualified technician, such as one from YourMechanic, can...

Q: Misfire in cylinder number 8.

Hi there. The issue could be the spark plug not firing on cylinder 8, the fuel injector not atomizing on cylinder 8, or there could be a burned valve or a burned head gasket. Check the spark plug on cylinder...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...
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...