Q: PO304

asked by on

Checked cylinder 4 for spark, no spark, Checked cylinder 3 for spark, good spark Switched cylinders 3 & 4 engine ran rough Checked spark on cylinders 3 & 4, no spark, Checked cylinder 2 for spark, good spark Switched cylinders 2 & 4 engine ran more rougher Checked for spark on cylinders 2, 3, & 4 no spark on none Seems like there is something wrong on cylinder 4, what can I do?

My car has 78000 miles.
My car has an automatic transmission.

Hello, thank you for writing in. Between the tests you have done, and the diagnostic code for a misfire on cylinder 4, you may have an issue with the ignition system. You will want to check the ignition wire, the distributor, and the spark plug for fouling. You can test the ignition wire with a spark tester. This is the safest and easier way to do so, although there are other ways. Make sure the spark plug does not have excess carbon build up or oil. These would be signs of more serious issues. While there are several other components that can cause these issues, start with these and take further diagnosis from there. For more help resolving the issue, contact our service department to schedule an appointment.

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

Q: Engine misfire, StabiliTrak wiring problem 2010 Chevrolet Equinox

Hello - these are likely unrelated problems - although all frustrating. The engine misfire will require further diagnosis based on ignition codes. There was likely another problem code - perhaps for an ignition coil or misfiring plugs issue. It is...

Q: I got new water pump put in my 2003 ford tarus and now my ac and heater only blow from defrost vents any reason why? I asked the

Hi there. Typically service to a water pump does not impact the heating or coolant system's distribution of air into the vehicle. If the water pump was not working correctly, or if there was an obstruction in the heater core,...

Q: will it cause more damage if I continue to drive with a burnt out valve in the engine?

Hi there, thanks for writing in. Unfortunately, yes you can do more damage by continuing to drive with damaged valves. The misfire will cause damage to the catalytic converter, which is a critical emission device. Damaging the catalyst can cause...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.