1997 Ford Ranger 2wd 2.3L 5-speed

When I first bought it, about 6 months ago, I was averaging 20 mpg. Lately, I've been averaging about 14… Needless to say, it shouldn't be that low for a 2.3L.

There's been no change in my driving habits over that span of time.

The only thing I've done is replace the air filter and back-flush the cooling system. The tires were a little under-inflated too; filling 'em up should have helped, but it didn't.

Engine runs fine, nothing abormal stands out.