Q: Spark plugs 1 and 5 are black, car is giving a multiple random misfire code, car has sat for a while 7 months ,maybe bad gas

asked by on November 21, 2017

My car has black spark plugs on cylinder 1 and 5, car is giving a p0300 code, multiple random misfire, may be due to the fact cars been sitting for 7 months with no fuel stabilizer, but if thats the case why only 1 and 5 are misfiring? these are new spark plugs too

My car has 98652 miles.
My car has a manual transmission.

Engine misfires can be caused by many different problems and are generally caused by either a spark or fuel issue or in some 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 and inspect your vehicle.

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

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

Grinding sounds during braking, burning smell

Hi there, thanks for writing in about your 2009 Ford Flex. The pad material used in the pad can be noisy and cause a light burning smell after use. This is normal and doesn't require any fixing unless you change...

AC compressor idler pully won't spin

The AC compressor pulley or compressor clutch has a bearing inside of it that enables the pulley to spin without the clutch being engaged. When the air conditioning is turned on inside the vehicle the compressor clutch will engage and...

Throttle stuck open

First, I would check to make sure that there is not a floor mat stuck under the gas pedal. Once that is ruled out, I have a strong suspicion that you're either having a problem with the acceleration pedal position...

Related articles

A Buyer’s Guide to the 2012 Infiniti G37
The The 2012 Infiniti G37 is a sporty vehicle that looks as great as it performs. It’s a head turning vehicle that could be the perfect entry point to the luxury market for many people. Key Features The driver’s seat...
A Buyer’s Guide to the 2012 Infiniti FX
There’s There’s just something unmistakable about the overall design and aesthetics of the 2012 Infiniti FX. With sleek lines and a classic feel, some might think this SUV is all about looks. However, it also packs exceptional performance and plenty...
A Buyer’s Guide to the 2009 Mazda Tribute Hybrid
2009 2009 marked the end of the very short life of the Mazda Tribute Hybrid. All told, the automaker produced fewer than 700 models, and it was ultimately retired well before the Tribute itself ceased production in 2011. For the...