Skip the auto shop - Our mechanics make house calls

Q: How often show VM dealer need to clean fuel injectors. Still misfiring after fuel injection service

asked by on

Second shop look at diagnostic codes, shows 2nd cylinder misfiring and replaced dirty spark plugs. Still getting check engine light. Since 1st shop did fuel injection service the 2nd shop said only VM dealer can do fuel injector cleaning to stop misfires at slow speed. What do you suggest?

My car has 124000 miles.
My car has an automatic transmission.

A: Hi, thanks for writing in. Misfires can hap...

Hi, thanks for writing in. Misfires can happen for many different reasons beyond just dirty fuel injectors. This may be due to a vacuum leak, but it can also be caused by a weak fuel pump (low fuel pressure) or a faulty fuel pressure regulator. It can also be caused by ignition misfire due to fouled spark plugs, bad spark plug wires, or weak ignition coil, a bad mass air flow sensor, a faulty crank position sensor, a faulty camshaft position sensor and many others. The best approach to identifying a misfire due to the broad spectrum of possibilities is to hook the car up to a scanner to download any fault codes that may be registered in the computer. These will further indicate more specifically what the cause of the misfire may be. If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose this issue for you, and make or suggest any repairs as needed.

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: Traction control light on

Hi There, Your car should be safe to drive, however it may need to be looked at to determine what is causing the traction control light to come on. Your car is equipped with wheel speed sensors at each of...

Q: MOT failures - repair work

Hi there. It's really difficult for us to give you an accurate estimate on repairs without inspecting the vehicle first. The inspection allows us to diagnose what is causing the tail light malfunction and emergency brake issues that your MOT...

Q: Shaking when in overdrive

Hi there. Check the fuel system and see if the fuel injector for cylinder number 2 is malfunctioning. The code P0402 means that the EGR is not functioning and the code P0174 means that Bank 2 is lean, which is...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
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.