Q: Engine is misfiring on my car

asked by on

The engine is running roughly on my car. It seems like the engine is misfiring; it bucks and vibrates. I did a tune-up (replaced spark plugs and coils, and air filter), put in fuel cleaner, and removed the idle air control valve to make sure it wasn't stuck. None of that helped. Could it be the mass airflow sensor? Someone had suggested to me that I should unplug the sensor and start the car to fix the problem, but that didn't work. Any ideas?

A faulty mass air sensor can cause rough running due to the injection mapping being improperly set. Unplugging the sensor can, in some cases, cause the rough running to clear up as a fault is set and the engine computer runs the vehicle off of preprogrammed values.

Since this did not help, the first thing to look at is the possibility of an unmetered air leak or vacuum leak. A smoke test of the induction system is a quick and easy way to locate an induction system leak. You may also want to have fault codes cleared and then read out after a drive cycle to see what comes back. A faulty oxygen sensor for example, can also cause rough running issues. You may want to enlist the help of a mechanic who will have the diagnostic equipment and training necessary to correct this rough running condition.

Was this answer helpful?
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. Engine is misfiring on my car

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: Q: My car will start, but will not run

This may be a sign of a failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine. This valve is controlled by the...

Q: Noises starting while turning on 2006 Pontiac Solstice

The fluid in the rear end can be inspected for extensive wear on the gears inside and the drive shaft joints for any amount of play. Check all of the vehicles fluids to make sure they are full and clean...

Q: Heater blower surge

Hi There, It sounds like you may have a faulty blower motor resistor. Blower motor resistors are used to control the fan speed of automotive blowers. The fan speed can be changed either by switching the blower resistor resistance...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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 to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...