Skip the auto shop - Our mechanics make house calls

Q: Misfire in number 4 cylinder

asked by on

I have replaced the number 4 injector. Rechecked the injector plug, but still have a miss code come up for the number 4 injector.

My car has 135445 miles.
My car has an automatic transmission.

A: Hello. Check to see if the code defines a &...

Hello. Check to see if the code defines a "circuit" that is a wiring issue with No. 4. If it does, you have to look at the signal to the injector.

Using a mechanic’s stethoscope, it is easy to hear the characteristic clicking noise that should be present if you probe the injector body and compare the noise (if present) to that from adjacent known good injectors to see if your No. 4 is even operating. If not operating at all, check resistance across the two injector solenoid terminals and compare to FSM. Depending on the code, it is that possible there is a related "ignition" issue in that cylinder, too. Particularly since you are describing the symptom as a "miss."

If it is ignition-related, you could have a bad plug or plug wire for No. 4. If you replaced it with a "used" injector, by the way, it could easily be plugged. Injectors typically have replaceable internal filters and used ones should be cleaned ultrasonically on a professional cleaning machine. It is very economical, too. Typically around $17 each at the shops which are known to do exemplary work of this type. If you would like to have this looked at more thoroughly, a qualified technician from YourMechanic can come to your car’s location to inspect the code and perform any required repairs.

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

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: Master cylinder going bad

The master cylinder may be going bad if you notice the pedal going down to the floor with no signs of any brake fluid leakage, or if the master cylinder is leaking fluid from the back of it into the...

Q: Fuel promblem

You may have excessive dirt inside the tank that has clogged the fuel filter to the point that the dirt has gotten into the injectors, causing the misfire. Remove the fuel filter and blow through it to see...

Q: Cost of an engine swap.

Replacing an engine does require some extensive work that can take some time. The cost will vary by shop as each shop has a different labor rate per hour. If you know what the labor rate of a shop is...

Related articles

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...
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.
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.