Brand new to the site as of this date. I recently bought a 96 F-150 that appears like it has never seen a winter. I am from the north so things get rusty quickly. My question is what is the best gas mileage I can expect with this truck. It has 59K miles and a 4.9L 5sp. with a 3.55 Checked it one time and got a shocking 11.25 miles per gallon. Very disappointing for the way it runs. I used to get close to 20 in my 78 F-150 with the 4 sp. OD. Is this normal or is something wrong. I also have a minor exhaust manifold leak but I don't think that is the cause. Any help would be greatly appreciated. Thanks

 

Driving like a normal person and not a lead foot, you should be getting 15-18 city/hwy ...approx give or take. I got 14.5 on a trip to maine with 32" tires and a 6" lift, I was getting 16 or so before that.

 

I do not have a lead foot and take it easy. I live in the country so it is almost all highway type driving. I don't lug the engine and shift to soon nor I wind the gears either. I do have a cap but it is cab high and also it is 2wd. 8ft bed and a regular cab if it helps.
I rarely go over 60. The tailpipe is a light grey so it is not running to rich.

 

id do a complete tuneup, ignition coil, distributor cap, rotor, plugs, wires. check your tire pressure. check your converter too to see if its plugged.

 

A major tune-up was done by a Ford dealer less than 14K miles ago. It seems to run to good for needing a tune-up, do you really think that might be the problem? Does the computor store up codes if prior problems were sensed? I don't or haven't had a check engine light since I have had it. I have only had it for going on 3 months and have not put 1K on it yet.
One thing that occured to me is with the slight exhaust leak could a knock senser be retarding my timing?

 

Airfilter dirty?

 

Thanks for the reply. Checked air filter and it looks like it was just changed.

 

check for PCM trouble codes. You can pick up a tester at Autozone for 20 bucks or so.

 

Your 96 has a mass air meter, which could be at fault. My dads 96 with a 351 went bad and was only getting 6-8mpg with no trouble codes, but black smoke on when on the gas pedel. I found that to be odd with a OBD-II computer.

 

What does the inside of the tail pipe look like? If it is really sooty I would probably bet on it.

 

I think if you look in your manual that Ford recommends changing the O2 sensor every 50K and since your entire engine performance revolves around it, might be worth $50 to try it.

 

Tailpipe is a nice light grey in color. I will try the oxygen sensor route.

 

Just got back from Crisfield Md. (Live near Baltimore). Truck has NEVER gotten over 14.5 before in any condition/load/speed.

Drove down Friday averaged 62mph/AC ON. 14.77 mpg

Drove back sunday evening, same roads....NO AC averaged 53mph....15.6mpg

Used the front tank for both ways.

Larry

 

Do you mean it has never gotten less than 14.5mpg?

 

carb 300's seem to be better on gas than the EFI's. My 460 gets better mileage then my 300.