Skip the auto shop - Our mechanics make house calls

Q: Car misfires; crack in manifold

asked by on

My car is having multiple misfires. There is a crack in the manifold where the o2 sensor is.

Hello. A crack in the exhaust manifold near the O2 sensor can cause some poor sensor readings to the computer. The crack will allow fresh air to enter the exhaust, which causes the sensor to tell the computer that there is too much oxygen. This will send a message the computer to add more fuel, thus causing misfires. If the engine is running rough and misfiring without any actual misfire codes, then the crack may be the problem and the manifold will need to be replaced by a trained technician. A mechanic would typically scan the computer for any codes and see what the fuel trim readings are in order to be able to verify that the crack is the issue. If you do not have the tools to do this or don’t feel comfortable doing this type of repair, I would recommend the assistance of a certified mechanic that can replace any components causing problems in your vehicle.

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
  1. Home
  2. Questions
  3. Car misfires; crack in manifold

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: I think timing - 2001 Honda Civic

Hi there. Assuming your friend replaced the crankshaft position sensor for a no-start condition or fault code stored, that should not have caused an extended crank or scraping noise unless the sensor was improperly installed. The cause may be unrelated...

Q: interchangable parts?

This question is hard to answer unless you know what part they want to trade. However, between a 2000 and a 2001 Honda Odyssey, you should be able to trade most parts except computer modules that are programmable and only...

Q: Car smoking and misfiring

The misfire alone is not enough to deem a blown head gasket. The fact that you have the white smoke present along with the misfire is sound evidence that this is the case. The white smoke means you are burning...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.