My crazy truck

my crazy truck is driving me nuts. It’s a 1990 F250 4X4, with the 460 gas engine. Empty, I get 16mpg, but if I put a trailer behind it–even an empty trailer!-- I get 19-20 mpg. why? Also, when I bought tires a few months ago, the tech informed me it had 464,000 miles on it. How’d they figure THAT out? Tea leaves?

How are you measuring the mpg?

If this were my truck I’d tow and empty trailer around all the time.

How many miles do YOU think are on the truck?

Some states record mileage at annual inspections and the data base is open to all inspection stations. I guess that’s where Car-Fax gets some of their information.

Your truck apparently likes to work. It was probably put into service working and doesn’t like running empty. It is like a German Shepherd. These dogs like to work and actually eat less working than they eat if they just lie around and get bored. Make your truck work so it won’t be bored and use more gasoline.

The more reasonable explanation is that somehow pulling a trailer breaks up the vacuum that builds up behind the truck. I have seen mesh used in place of tailgates. You might want to try this to see if it raises the mileage to your trailer towing mpg.

Removing/lowering the tail gate or installing an air gate on a pickup truck reduces fuel mileage.

With the tail gate in the up position, as the truck is moving down the road an air bubble forms above the box. This air bubble allows the air to come off the top of the cab, over the air bubble and off the back of the box. With the tail gate down/removed or with an air gate this air bubble cannot form. The air then goes over the cab, then dumps down into the box and then exits out the back of the box where the gate should be. This causes drag and reduces fuel mileage. I always get a chuckle when I see people with the tail gate removed or with an air gate installed on their truck thinking that it improves milege.

Myth Busters did a test to determine which did better. A truck with the tail gate up or one with the tail gate down. Two exact same trucks were driven at the same speed until they ran out of gas. The truck with the tail gate up got an extra 30 miles from a tank of gas than the truck with the tail gate down.


Are you getting your MPG’s from a computer readout as you drive or by calculating how many miles you drove at each fill-up?

If it’s your instantaneous MPG display inside the truck, I wouldn’t trust it. Maybe it gets confused when you’re pulling a trailer?

I really doubt you’re getting 16-20 MPG with a 4WD 3/4 ton truck with a 460. I have never seen a 460 powered anything do better than 12-13 MPG.

The 1990 F-Series didn’t have a trip computer.