See also:

When to Inspect the Engine Air Cleaner/Filter
Inspect the air cleaner/filter at the scheduled maintenance intervals and replace it at the first oil change after each 80 000 km (50,000 mi) interval. See Maintenance Schedule for more inform ...

Footnotes — Maintenance Schedule Additional Required Services — Severe
a) Check all fuel and vapor lines and hoses for proper hook-up, routing, and condition. Check that the purge valve, if the vehicle has one, works properly. Replace as needed. b) Or every four yea ...

Weight of the Trailer
How heavy can a trailer safely be? It should never weigh more than 454 kg (1,000 lbs). But even that can be too heavy. It depends on how the rig is used. For example, speed, altitude, road grades, ...