Skip the auto shop - Our mechanics make house calls

Q: Cylinder 4 misfire

asked by on

Cylinder 4 is misfiring. Code P0304 is shown. Put in a different coil didn't really help. Put in a new spark plug in cylinder 4 it runs better but still throws code and misfires. Car still sounds like is messed up and is shaking. But the one new spark plug did help it. Engine light is still flashing. What else can I do?

My car has 90760 miles.
My car has an automatic transmission.

A: It sounds like you may need an ignition con...

It sounds like you may need an ignition control module. It’s a small device mounted around the right front of the engine compartment. It has a plug with about a dozen wires connected. The module has a separate channel for each cylinder and sometimes individual channels drop out causing a dead miss in a single cylinder. The module is pretty expensive, and most parts places don’t take returns on electrical parts, so you may want to have it verified before you purchase one. Contact YourMechanic and they’ll send a mechanic to your home to check out your misfiring issue and keep you from spending money on parts that you don’t need.

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: Check Engine Light is on - P0302 and P0304. Ignition coil recently replaced.

The two Diagnostic Trouble Codes, P0304 and P0302, refer to cylinder misfiring. A faulty ignition coil, spark plug, wire, and so forth can cause a cylinder to misfire but there are other possible causes, too. Consequently, the only way to...

Q: Changed heads and now it won't start. Dodge dealer said no compression

Hi there. For the valve seats to drop out of the cylinder head(s), the engine overheat must of been severe. Assuming you followed proper procedure replacing the cylinder heads. This would lead me to believe it to be the compression...

Q: Car died with a low oil indication

The engine misfire codes could be an indication of why the car died. When the engine is misfiring, it can cause a very low power situation, can cause the engine to shake, and can cause the vehicle to stall out...

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 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...
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.