4Runner

I have an '03 4runner and I’ve been using more gas in the same amount of miles that it’s used to. what could be the issue?

How do you maintain your vehicle ?

By the book (owner’s manual) ?
When it starts to run bad ?
When your mechanic recommends it ?

When was the last time a complete tuneup was done ?
How often do you change the oil?
Keep in mind now that it’s winter if you drive around with ice and frost on your car especially on the freeway it’s going to hurt your MPG.

Audit your maintenance and get back with us. The spark plugs should have been replaced by now and if it has over 100k then the distributor cap & rotor, and spark plug wires should be done. Check the air filter too.