Q: only passenger side plug is carbon build up driver side is clean change plug doing same thing

asked by on

my car was hesitate when go up hill and start to go change plug and wire only passenger side plug was heavy carbon build up driver side was clean burn after 100 mile car was acting up same problem check plug only passenger side plug carbon build up again

My car has 90000 miles.
My car has an automatic transmission.

Hello, thank you for writing in. The most common cause of carbon build up on the spark plugs is unburned fuel, also known as "running rich". Despite the assumption that the injectors are to blame, it usually has more to do with how the spark plug is firing. Since it has happened to two separate sets of plugs, you are concerned with the ignition circuit at that side or plug. The coils and wires are the first to rule out. Oil being burned in the engine can also cause extra carbon deposits. If the ignitions system checks out, start looking for signs of an internal oil leak. For more help with diagnostics and repairs, contact our service department to schedule an appointment.

Was this answer helpful?

If only one side of the motor is clogged with excessive carbon build-up, it may represent a lean mixture issue with the fuel injection system. Unless you are experiencing loss of power, fuel mileage of the engine is running extremely hot, I wouldn’t worry about it. If you experience those symptoms, have a professional mechanic inspect the fuel system for issues.

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
  1. Home
  2. Questions
  3. only passenger side plug is carbon build up driver side is clean change plug doing same thing

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: Why do I hear a squeak on the upper front side of my car when I go over driveways for example?

You should have your lower ball joints checked for wear. Also the sway bar bushings and links may be worn out. Have the entire front suspension checked for worn out or defective bushings or ball joints in the steering system....

Q: Ignition switch won't turn all the way off

It would appear that the vehicle has several problems that will need to be addressed separately. The radio staying on is probably caused by a switch that is not turning off all the way. This may also be related to...

Q: Jerks when downshifting and slow. 2005 Mercedes Benz E55

You may have a broken motor or transmission mount that will allow the transmission or engine to move excessively. Also another possible cause is the transmission torque converter sticking when commanded to release. There are technical bulletins to flush the...

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...