Tune up

Step by step guide on how to tune up an automotive internal combustion engine, this article pertains to all cars.

Difficulty Scale: 5 of 10

Tools and Supplies Needed

  • Spark plug socket
  • Ratchet
  • Extensions
  • Carburetor cleaner
  • Shop towels
  • Fuel filter release tool (some models)
  • Spark plugs
  • Fuel filter
  • Air filter
  • Plug wire set (some models)
  • Screwdriver set
  • Protective gloves and eyewear

Begin with the car on level ground, in park with the emergency brake set.

Step 1 - Many times an engine tune up can be accompanied by a check engine or service engine soon light. If this is the case, connected a trouble code reader to retrieve diagnostic trouble codes to isolate the misfiring cylinder or malfunctioning system.

Code Reader

Step 2 - A fuel filter is used to clean fuel before it enters the fuel injection system. This filter should be replaced within an engine tune up. (Note: Some vehicles are not equipped with the an external filter, these vehicles filter in located inside the fuel tank and are good for the life of the car in most cases.)

Fuel Filter

Step 3 - A mass air flow sensor measures engine air intake volume while generating data for the computer. This sensor processes large amounts of air and after many miles of usage, the sensor element becomes contaminated and must be cleaned using a sensor safe carb spray.

Mass Air Flow Sensor

Step 4 - An engine air filter is designed to removed dirt and other containments from the air intake system, inspect and replace the air filter.

Engine Air Filter

Step 5 - A throttle bore actuator is used to control air flow into the engine's intake manifold, and onto each cylinder. Manually controlled units (throttle cable) use an idle air control valve (IAC) to adjust engine idle speed. These devises process large amounts of air much like the mass airflow sensor. After many miles of operation a condition called coking occurs which hinders performance characteristics. These items must be serviced (cleaned) to operate correctly.

Engine Throttle Bore w/Idle Air Controller


Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2013-11-28)