Q: How to replace the Air Filter Box in a Nissan Frontier?A: To replace the air filter on a four-cylinder engine, begin by removing the wing nuts, clips, and filter box cover. Disconnect the breather hose and remove the box base. On V6 engines, disconnect the electrical connector, loosen the retaining clamp and detach the vacuum hoses. On 3.3L V6 models, detach the spring clips and remove the air filter cover and mass airflow sensor. On 3.5L V6 engines, remove the filter element from the removable carrier. Remove the air filter box mounting bolts and disconnect the crankcase breather hose. To install, switch the removal steps going from the final step to the first step.