Routine Maintenance

• Fuel injectors should be changed every 80,000 to 100,000 miles as a part of your vehicle's routine maintenance plan. Given the high-mileage requirement, fuel injectors tend to be low-maintenance parts.
  
  

When Injectors Fail

• Aside from routine maintenance changings, fuel injectors may fail and need to be replaced sooner than anticipated. Several factors, including electric shorts and internal damage, may cause the injectors to fail. The most common reason fuel injectors fail is that they become clogged by sediments in the fuel system and by-products of improperly burned fuel.
  
  

Interim Maintenance

• To stave off the clogging that leads to injector failure, fuel injectors need interim maintenance. Injectors should be cleaned every 25,000 to 30,000 miles to prevent any issues that may cause them to stop working effectively.
  
  

Signs of Faulty Fuel Injectors

• Faulty or failed fuel injectors can cause a car to run rough--or not at all. Fuel injectors that do not deliever enough fuel will make the car appear to run out of gas, choke down, sputter and stall. Fuel injectors that deliver too much fuel will produce the same symtoms, accompanied by a strong smell of gasoline.
  
  

Testing the Fuel Injector

• A fuel injector's performance is tested using a voltmeter and stethoscope that attach to the electrical connectors to measure the injector's output and efficiency. This is not something a novice mechanic should do. It is best to have your fuel injectors checked by a qualified mechanic to ensure the testing is done correctly.