88 2.3 ranger fuel milesge

[2000f350v10]

my truck is an 88 ford ranger 2.3L 5 speed, 4x4. 3" body lift, with 30x9.5x15 inch tires. previous owner supposedly installed a rebuilt carbed mustang 2.3 and used the ranger EFI. after fixing the timing that was way off, new cap, rotor, plugs, wires, rear main, oil pan gasket, clutch, slave cylinder, I have the truck where i think it should be(that is, until I turbo it). My question is, I suddenly am getting whorrible fuel mileage. I was getting around 16-18, with mixed driving, which i figured wasnt too bad since its a 4 cyl turning 30" tires, but suddenly it has plummeted drasctically. id be surprised if im getting 11-12 now. I redid the exhaust, it was exiting in front of the rear tire, now it exits in the rear, and replaced the water pump. seems to me the truck might be running a bit cooler with the new water pump, but i could be imagining that. It has been windy here, so i have had problems getting to 70 mph on the freeway, and keeping it in 5th gear at 70. The timing is dead on, all marks lined up, set at 10 degrees advanced. The truck has always been slow, which i figured it would be(especially compared to my V10 Super duty), but i figured i should be able to run 70 mph on the highway somewhat easier. Sorry for the long post, just trying to find my lost fuel mileage. I was thinking about going to a smaller tire, a 235/75/15 but figured id ask before buying new tires. o i also just replaced the ball joints and had the front end aligned.

 

[Bryan22]

2.3 with anything over 30 inch tires and stock gearing... 5th is only for downhill. As for the mileage, hard to say without more info on what has been done to it, any codes?

 

[2000f350v10]

no codes. truck runs great. as far as I know it was a stock rebuild on the motor. The dizzy, cap, rotor, plugs,wires are new, new water pump, alternator. truck doesnt ever spit or stutter. always starts up great. idles around 1,000 rpms. I wanted to downsize the tires anyway to 235/75/15 so I can actually use 5th gear more. I figured that should help mileage a little. Im gonna change the fuel filter soon. Im just trying to figure out why all of a sudden my mileage dropped so much. Also, the truck has black steel soft 8 wheels on it with the 30s. I have a set of aluminum explorer wheels, would I be better off with the 235/75/15 tires on the aluminum wheels for weight reasons?
i was thinking about regearing but dont want to spend too much as I just did a ton of work to the truck with the front end rebuild, clutch, etc.

 

[2000f350v10]

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Well today I changed the fuel filter, and put on the aluminum explorer wheels with the 235/75/15 tires. They seemed to weight half as much as the steel wheels with the 30s on them. Gonna fill it up tomorrow and report back with fuel mileage.