poor mpg

Very true. As a side note, there is a strong smell of raw fuel in the air when the vehicle is idling. Sometimes this thing idles at about 800 RPM's on a cold start & most of the time it idles at 1200 RPM's on a cold start & stays at 1200 RPM's when warm. Blipping the throttle has no effect on the idle.

Pull the air filter cover and look down into the carb while the truck is idling. You might need a flashlight. You don't want to see fuel "blobbing" into the primary side (left side) of the carb but if you do that is where some of your poor mileage is coming from.

You might also want to check your pcv hose / valve for cracks for a gas aroma problem.