Q: Misfire cylinders 4 and 7.

asked by on

My truck has been misfiring on cylinders 4 and 7. I've changed the plugs and coils fuel injectors are clicking and I've ran a compression test both cylinders were around 165-170. At first it was throwing a lean code on bank one as well now is throwing a rich code. Cylinder 4 and the rich code seem to be intermittent because they go from stored codes to pending codes. The lean code was the same as well. I've checked for spark checked for vacuum leaks and checked for any fuel leaks. I changed the fuel filter and my fuel pressure was good as well.

My car has 145000 miles.
My car has an automatic transmission.

You need to check the PCV tube that goes behind the intake and connects into the back side. The hose can get a leak in it, causing a vacuum leak on the back side. This will create lean conditions that may be worse for cylinders 4 and 7 specifically on this engine.

If the hose is good then try and have the injectors replaced or cleaned for these two cylinders. You could swap them with different cylinders to see if the problem moves along to the other cylinder, doing so will help pinpoint the issue.

If you decide to get the car looked at, consider YourMechanic, as a certified technician can come to your location and diagnose your car’s misfire. An accurate repair can then be made once the problem has been pinpointed.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 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!
  1. Home
  2. Questions
  3. Misfire cylinders 4 and 7.

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: Cylinder misfire

Hi, thanks for writing in. The strong smell of fuel is usually attributed to a failing mass airflow sensor or O2 sensor. These two sensors control air/fuel adjustments and can cause a misfire if they have triggered a lean fuel...

Q: Car has begun to run rough

This may be related to a faulty throttle position sensor or potentially a dirty or failing mass air flow sensor. The mass air flow sensor monitors air intake as it is mixed with fuel prior to being injected into the...

Q: Power steering fluid leak

Hello. The vehicle's power steering consists of a few components, as well as a pressure line side and return or low pressure line side. Most commonly, the high pressure side can experience leaks from wear or the low pressure side...

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 Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...