Coltenandruchiw

So I just bought a 1996 f150 single cab long box 4x4 with the 300 i6 5 speed. It’s an awesome truck but there’s a few issues. The truck barely crosses 65mph and averages 9mpg. I never cross over 2000 rpm. Please give any feedback and ideas. Thanks

JCiesla

When you say the vehicle barely crosses 65mph and 2k rpm, do you mean it can't or you just don't take it there? Are there any studdering or driveability issues or is the only issue purely the low MPG?

77Ranger460

9 mpg sounds about right for that truck running oversize tires with aggressive tread

Coltenandruchiw

I just never take it over 2 grand just for longevity of the motor but I am just worried about the mpg mainly

Coltenandruchiw

They appear a lot bigger then they are in the pic. They are 31s and not too aggressive

JCiesla

Gotcha. Well I agree the tires might not be helping but 9 seems pretty low. I'd definitely clean/replace the air filter and if you can, replace or at least check the spark plugs for cleanliness and proper gap and if neither of those help (enough) replace the injectors or run a fuel system cleaner. Without any other noticeable performance issues or CELs, I'd say those are likely culprits for poor fuel economy. They're at least the easiest/cheapest things to take a look at first.

David Young

I get around 17mpg with my 91 4X4 with the 300 i6 and 5 speed. But I have the short bed with the factory size tires and 3.08 gear ratios

DarrinT04

how old are the spark plugs?

Steve83

That & all the REST of the truck's details need to be in your signature so we can review them without digging back through your posts, as this caption explains:


(phone app link)Are you saying it WON'T go faster, or that you choose not to?I doubt it. It would be rolling coal all the time. Did you calibrate the speedometer (PSOM)? Click this & read the caption:


(phone app link)About 20 years ago, I took the 4.9L out of a wrecked F150 & put it into my '83 Bronco. Shortly afterward, I accidentally rolled it on the highway, and replaced the body with an '82. I drove it like I stole it (<3500RPM <115MPH) on-road & off- until that body started falling apart. Then I bought a '93 with a blown 5.8L, stripped both trucks, and put the 4.9L onto that frame. I still drive it the same way (but with periods of disuse, because I have several other vehicles), and it has nearly a million miles without a rebuild. It has always gotten 12-14 MPG, and runs the same as it did the first mile I put on it.

Engines are made to run. Longevity depends on the quality of maintenance & repairs - not RPMs or speed. Do you follow the maintenance schedule?


(phone app link)

Do you use top-quality parts & recommended procedures? Stay out of the zone, and read the Haynes manual cover-to-cover at least once:


(phone app link)

This & its caption contain a lot of Ford information about MPG:


(phone app link)

Coltenandruchiw

How do you find out what gear ratio you have?