My 97 Dodge Van Sportsmobile w/ Quigley 4wd(62,000 MI) with a 359 gets 12 mpg, does anyone know of an engine swap or carb swap that will improve gas mileage. With todays prices per gal, I think its my last hwy camping rig ( i'm 77 yrs old). I'm pretty mechanical and have a nice shop, w/ tools and engine hoist. I also am in no hurry. I really like the rig.

Thx from Lopez Island, Wa

 

That's likely about as good as its going to get, given what you have. You can try the usual stuff, full tune up, and replace the oxygen sensors. (NTK or Denso brand only please.) Going to a carb is NOT going to give you better mileage, it'll be worse.

Changing to synthetic fluids for oil, and differentials might give you a little bit as well.

 

Well, it has the aerodynamics of a brick. Unless you swap in a diesel, there's not much you can do. The 4X4 will really eat the fuel. The only thing I can think that would eat extra fuel is if your thermostat is too cool of a setting. If it's the stock unit (195 degrees), all you can do is try to reduce rolling resistance. Make sure the front end is in good shape and aligned properly, brakes aren't dragging, maybe go with less aggressive tires and so on. My '96 Ram 1500 4X4 gets 12-13 mpg on a good day. I got 14 once, I think, on a long run down hill with a tail wind.

 

I could actually get 15 or 16 on the freeway, on cruise...... and it IS pretty flat around here.... I think I actually managed 18 on the freeway once. But, I was never able to repeat that. The truck has *slightly* better aerodynamics...... but, only "slightly".

That was on my 96 2500 4x4 with the 5.9 gas, auto. I can only dream of 14mpg with my 98.........

 

It sounds like it is running like it should

 

that's about right