Just wondering if there are any post on what all to do to get better mileage out of the 3.9? I know my alignment can't be fixed right now but i still need some way to get better mileage, done the regular stuff like wires,plugs, cap and rotor. Any help would be nice. I would do alignment but they want me to buy all new bushings and thats to much right now.

 

That's pretty much it, make sure the air filter is clean, tires are within 10% of capacity, synthetic fluids wherever you can.
Any "mods" for better mpg's (if they work in the first place) would take tens of thousands of miles to make back their cost, so the normal maintenance stuff is still the best bet.

 

I did put cold air intake but now a lot of people at work are saying it just lowers my mileage, is this true if it's the only mod I have done?

 

well its your truck have you noticed a drop since the swap? only you have the vehicle specific mileage of the before and after

 

It seems better but I mainly meant do cold air intakes really help mileage? A mechanic i talked to said you have to have so much pressure in the intake and the cold air doesnt have any pressure. I think hes wrong lol.

 

Alignment out of specs would definitely be detrimental to the MPG. A good tire shop can do a 4 wheel alignment job for anywhere from $80 to $120.00. But you could probably replace the bushings yourself and save money.

I don't know about your truck but my own MPG increased by about 3 or 4 in town and 5 or 6 more mpg on the highway when I put in a 180 degree thermostat. I also removed the air snorkel and enlarged the opening in my air intake box with a dremel tool. I just run a Wix/Napa Proselect paper air filter and I get about 23 mpg around town, more on the interstate. I get good MPG with Autolite 3923's and Belden plug wires and a distributor cap and rotor button with brass contacts, all from Napa. Use good quality gas and keep the throttle body clean, run a bottle of Gumout Regane every 3 or 4000 miles, keep the tires inflated to the right psi and get the alignment and suspension back in specs and keep the oil changed regularly. Some say keeping a good slick coat of wax on the truck will reduce the drag coefficient and help the MPG a little. People also say synthetic oil helps MPG, but that might not be so good for the engine if it has high miles on it. Opinions vary on that one. Other than that just drive sensibly and try to combine your short trips.

 

don't floor it Go easy on it.... Yea I know it's hard in a v6 but it does help, i must say the method is easier in a v8 when your not in a racing mood.

 

One other thing was my MPG seemed to get a lot better especially on the highway after I installed a V8 throttle body. Truck pulls harder from a stop too.

Jimmy

 

By air snorkel do you mean the ribbed hose from the tb to the intake box? I do think the rough texture of it would reduce airflow. I want to at least have it where i can chirp the tires, my truck feels so worn out lol but then again i don't know if tires make much diff on that. They are 275/60 r15 if i remember right. Also, is the v6 suppose to have low end power or high end? I only feel power after about 60mph.

 

with a v8 TB, you will lose bottom end and gain top end...