So maybe im being dramatic but it seems like my truck gets pretty bad gas milage. It's a 96 F150 xl. 4x4 4.9l. It has 3.55 gears and 31x10.5 A/T's. It has 1.5in. spacers in the front and slightly bigger blocks in the rear. I fill the front tank up, usually put about 16 gallons in. The rear tank is empty and i have no load. I drive mostly city type driving. I get about 180 miles untill i fill up, another 16 gallons. That seems pretty bad to me thats like 12mpg? any ideas why it's so bad? thanks

 

Sounds pretty average to me or even slightly above average with your tires. You could bump your timing and see if there's knock. If you want to stick some cash into it you could always do a tune up and upgrade your ignition then bump your timing even more. Electric fan really help gain some mpg too.

 

What is the stock timing on these things? what range would you suggest to stay in?

 

stock is 10 degs most turn it to 12 or around there just to keep it running on 87 gas. the rest of yall throw in yalls opinions haha

Kyle

 

Hell, I got 10 on the first trip I made with my 94. I did the ignition upgrade, bumped the timming, and added some 33s(3.50s right now) and I managed 12 on the hwy. But usually get about 10mpg with day to day driving.

 

Recalibrate your speedo so the odometer is correct and you'll see the actual milage is 13-14mpg.. and that is about right for city driving.

 

I onwed the same year, same set-up, same tire size vehicle and never got better than 13.5 mpg average. And drove it highway 85% of the time.

 

Have the same problem on my 5.0 but it might be my right foot..lol....it has been just sucking it down through this winter.. i use overdrive all the time, i will report my next fill up and mpg b/c i run the front tank mainly also...good luck everyone!!

 

It sounds like most 5.0's can get up to 13.5 degree timing with 97 octane. My 87 5.0 with the ignition upgrade pulled 12 degrees but I also run 32's so this will effect how much timing you can advance.

Also do you fill with 10% ethanol mix? I know I get a good 2 to 3 mpg less when I use ethanol blend.

 

i hav the same setup, 90 with 4.9 and 31/10:50 tires. theres a formula for the tire difference, anyway im getting 15 mpg. ill see if i can find the formula and post it, because you have to compensate for the tire difference. ofcourse you have to enter your stock tire size then the tires you have now and it gives you the formula to get the proper mileage. http://www.dakota-truck.net/TIRECALC/tirecalc.html