I have a 1982 22r with 161,000 miles. It came from a bad home and I am trying to straighten everything on it. I have two issues that I can not quite get. This thread will be for the fuel consumption. I have given the pickup a tune-up and not much happened. Rough idle, terrible mileage with stock sized tires, super rich nasty exhaust. So new alternator, new carb, and now better response, faster speed, same fuel mileage and nasty exhaust at regular speed and idle. I am not hot rodding this thing. The idle is still terrible at the start, but after getting to temperature it does idle ok, not great. My plugs are hershey brown which should be good. I need help figuring what is the deal and improve my mpg. Thanks,
keep your powder dry and stay out of the overflow

 

Have you checked compression? If i remember correctly if you have terrible compression, on top of everything else you also will not get good milage.

 

you keep saying nasty exhaust. its quite possible that your cat is getting plugged. this would make it hard for the motor and possibly ruin your mpg.

 

maybe check the AUX pump on the front bottom driver corner of the carb if that diaphragm in it goes bad it will allow gas into the vacuum lines and it will run like that. To check with the truck off pull the vacuum line off and see if there is gas in it. If it is bad you can just cap it off if you dont want to buy a rebuild kit for just that part. it only adds more gas during cold conditions mine is capped and it runs fine.

 

Good plug wires/cap/rotor? A good strong spark will help with the running.

 

This same thing happens to my 82 4WD... Same symptoms as you describe with the nasty rich smelling exhaust. Mine is also pretty gutless for only having 177k miles on it.