☰
GET A QUOTE

Q: Would bad spark plugs cause misfire in cylinder?

asked by on March 10, 2018

I have never replaced my spark plugs (30k miles) and they are the wrong brand plugs. My engine is misfiring in cylinder 5 and the cylinder is filling up with fuel and igniting causing flames to shoot out a hole in my exhaust pipe when I was checking back pressure. Could this be a cracked head or bad spark plug?

My car has 139200 miles.
My car has an automatic transmission.

Recommended Services

Engine is misfiring Inspection $94.99 - $114.99 Get a Quote
Or For Any Other Auto Repairs Get a Quote

A misfire could be caused by a bad spark plug. It could also be caused by a bad coil, fuel injector, an air leak, a compression problem, or a camshaft problem, or yes, even a bad head gasket or a cracked cylinder head. So it is way too soon to assume the worst. If you’ve never changed your spark plugs, that is a good place to start because it’s time anyway. But I wouldn’t spend money on any other parts until you get a proper diagnosis. You can have that done at your convenience by contacting YourMechanic. They can send a technician to your home or office to check out your Misfiring problem and let you know what is the solution.

Dodge
2004
V8-4.7L
Ram 1500
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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

How Often Should my Ignition System Be Inspected?
Periodic ignition system inspections (https://www.yourmechanic.com/article/how-often-should-the-ignition-system-be-inspected) should follow the prescribed maintenance intervals (https://www.yourmechanic.com/scheduled-maintenance) as recommended by the vehicle manufacturer. Maintenance schedules are published in the owner’s manual of every vehicle. Routine ignition system inspections aren't as frequent as they used to...
Read more
Parasitic drain on battery.
Hello, it sounds like you are really close to a solution since you know what is causing the draw. I would check with the relay that powers up the PCM. Locate the PCM relay in your owner's manual or fuse...
Read more
While driving at night, headlights occasionally turn off, so using high beams which do work
It sounds like there is a problem with the headlamp circuit. At first, I was going to say that the headlights have a poor ground connection, but then, looking at the wiring diagram for your vehicle, I noticed the high...
Read more
Constant humming when above 35 mph
With less than 50,000 miles on your 2013 Jeep Patriot, a constant humming above 35 miles per hour is a concern. My first guess would be wheel bearings (like you checked), or perhaps a disc brake pad that was stuck....
Read more
Car cannot pick up fuel
The first step is to check fuel pressure at the fuel rail. For your vehicle, pressure should be 30 to 40 PSI while running and 35 to 45 PSI with the engine off. Since you've already replaced the pump, if...
Read more
Check engine light on , 2012 Hyundai Sonata
Hello, a common issue with Hyundai engines is the camshaft and crank shaft position sensors failing consistently. These sensors detect where the camshaft and crankshaft are in relation to each and when they fail, the vehicle usually goes into limp...
Read more
My car is on anti-theft mode and I can't turn my car on. I don't have a key for that
Hey there. The vehicle has an integrated anti-theft system (https://www.yourmechanic.com/article/how-to-shut-off-the-anti-theft-device-in-your-car-by-jason-unrau) that can not be turned off or bypassed for a no start. If you lost all the factory keys, then you will need to have new keys made and programmed...
Read more
Car won't start after i changed both knock sensors and harnesses.
You can try to see if there are other codes stored in the computer. Usually, the connectors are different so you can't mix them up but that may be a possibility. If there are no new codes, make sure there...
Read more
I can not lock or unlock the doors on my 2010 Cadillac SRX
Hi there. Although your Cadillac is a rather complex vehicle, the power door lock system is a relatively simple system. When you press the lock or unlock button (located on your key, or inside your vehicle), the power door lock...
Read more

Related articles

2012 Toyota Sienna vs. 2012 Dodge Grand Caravan: Which One Should I Buy?
The battle of the minivans: Toyota Sienna versus the Dodge Grand Caravan. Both of these comfy people-movers provide options galore, and the minivan is meant to get everyone where they need to go safely and quickly, at a reasonable cost...
Read more
Dodge Certified Pre-Owned (CPO) Car Program
Drivers Drivers who are shopping around for a used Dodge vehicle may want to consider cars under the Dodge certified pre-owned program. Many manufacturers have a certified pre-owned (CPO) program, and each one is set up differently. Read on to...
Read more
Industry News for Automotive Techs: November 5 - November 11
Tesla buys Grohmann Engineering, Ferrari's future hybrids, next-gen Dodge Charger and Challenger, Nissan e-Power system, and YourMechanic recognition.
Read more

Browse other content

Estimates
Maintenance
Services
Cities