Skip the auto shop - Our mechanics make house calls

Q: Engine misfiring?

asked by on

Vehicle has been been running fine always had loss of power issues when accelerating. Check engine light started Blinking and upon acceleration car started to bog down. Been reading that misfire issue but what would make car do this. Coil pack,fuel pump,crank shaft, clogged CAT?

My car has 221000 miles.
My car has an automatic transmission.

Engine misfires can be caused by many different problems, but there are a few suspects that occur more than others. Generally, misfires are caused by either a spark or fuel issue or in cases, a combination of both. Spark related problems generally will result from things like ignition coils, crankshaft position sensor, spark plugs, spark plug wires or ignition modules not working properly. When the misfire results from a fuel related issue, this is commonly related to a lean fuel condition (lack of sufficient fuel supply to the motor). Fuel related misfires can be caused by many different things such as low fuel pressure, faulty or dirty fuel injectors, a faulty O2 sensor, a dirty or failing mass air flow sensor, a faulty or dirty idle air control valve or a vacuum or intake leak. When the fuel supplied to the combustion chamber is insufficient, this results in an ignition (spark) that is igniting a less than balanced load of fuel and air. This results in a misfire or an explosion in the cylinder that is much less powerful than the other cylinders. This creates a loss of power that resonates throughout the motor additionally causing other problems with ignition and fuel timing. Due to the number of different things that may cause an engine misfire, the quickest and easiest way to diagnose this type of problem is to hook the vehicle up to a scanning tool which will download any potential fault codes that may have registered in the vehicle’s computer as a result of the poor running condition. I would recommend having an expert from YourMechanic come to your location to diagnose your misfiring problem.

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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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: Misfire on cylinders 3 & 4 need to know the easiest way to fix it

The best way to resolve misfires on your engine is to remove the ignition coil and the spark plugs on the affected cylinders. If the spark plugs appear to be in bad condition I would recommend replacing the spark plugs....

Q: Service Air Light On

There may be a few causes for why the Service Air light is illuminated on your Escalade. Assuming that we are not referring to the supplemental restraint system (SRS), it sounds like there may be an issue with the suspension...

Q: Car won't turn on

Hi, thanks for writing in. It sounds like the ignition switch and/or lock cylinder are bad. Your vehicle may be part of the GM Ignition Switch Recall. Go to safercar.gov and run your VIN number. The site will tell you...

Related articles

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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.