Technician A says that a dirty air filter can affect short-term fuel trim. Technician B says that a dirty air filter can affect long-term fuel trim. Who is correct?
A) A only
B) B only
C) both A and B
D) neither A nor B

Question

Quizplus · Accepted Answer

Both technicians are correct. A dirty air filter can restrict the flow of air into the engine, causing it to run rich due to the decreased oxygen content. This can be detected by the short-term fuel trim. However, if the dirty air filter is not replaced, it can lead to long-term problems such as fouled spark plugs, which can affect long-term fuel trim.

Technician a Says That a Dirty Air Filter Can Affect