I have a 1994 F150 4x4 with a 302 engine and E4OD tranny with 3.55 gears. I just drove to cincinatti and back to Tn 420 miles each way. Now there was an equal mix of uphill and down hill driving. I averaged about 11 mpg for the trip. I drove about 70 mph there unloaded and about 55-60 mph back with about 2500 pounds in the bed. Is there any way to improve this mileage besides slowing down to a crawl. I'm thinking I should've got maybe 15 mpg on the way there anyway and it was around 10.5. I actually got better mileage coming back loaded with a lot more wind drag. Maybe the catalytic converter is clogged or something? Any ideas or comments would be great. Thanks.

 

check/delete your cat.

clean injectors

https://www.ford-trucks.com/forums/9...ml#post9386491

 

Also try checking the fuel filter, and possibly a Sixlitre tuneup

 

I don't know how exactly to clean the injectors unless you just mean running some of that fluid from the parts store through it. I already put a new fuel filter on it a month ago as well as a new IACV and MAF Sensor. As far as a sixlitre tune up, if you mean buy a diesel that is way out of budget, although its not far from my everyday wants. Thanks.

 

sixlitre tuneup: ignition upgrade and timing bump (no 56K) - FSB Forums

looking at your original post again, you mention the catalytic converter. My truck had a pretty well blocked cat before I removed it. If it seems to be fine when idleing and at lower speed, but is lacking power when the RPMs rise and it's getting bad fuel economy, it could very well be the catalytic converter. When my truck's cat was plugged up, it made more power at 2,000 RPM than it did at 4,000 (factory peak hp). Also, when I removed the cat (and muffler for straight pipe exhaust), my mileage went from a fairly consistent 6-8 mpg, to almost 11.

 

like someone told me once on here "we are driving a vehicle that is as aerodynamic as a brick. so dont expect too many mpg"

 

^^^^^^

Love that quote!

 

I checked under my truck to see if I even still had a cat but I'm not sure of what I saw. I have 2 pipes coming out of the exhaust manifolds leading into one irregular looking thing right behind the motor. I saw no mufflers or at least nothing that looks like any muffler I ever saw. Now people are telling me that the thing in the front has to be a muffler because my truck isn't loud enough to be running straight pipes. Generally every muffler I've ever seen on a truck was further back under the bed. What do you guys think? Maybe a previous owner did away with the mufflers and left the cat?

 

that is what it sounds like they have done to me. a cat will reduce exhaust niose quite well. and if it is plugged up it will even more so. un bolt the irregular looking thing at the front of it or the exhaust off the back of it and get a long steel rod, take the rod and a big hammer and drive it through the cat and bust all the stuff out of it and let the motor blow it out of the housing. then you will have a nice sounding hollow muffler. i have done this many times and they have sounded nice and throaty.

 

OK.. but what size tires are on it? Oversize tires hurt fuel milage in 3 ways.
1) They slow down the speedometer so you're actually driving faster than you think you are and that increases fuel consumption.
2) They slow down the odometer so your're actually travelling further than it shows, but the lower accumulated milage makes your fuel consumption calculation look worse.
3) They're heavier and it takes more energy to spin them.

The fix is easy too, just recalibrate your PSOM.. https://www.ford-trucks.com/article/...nd_bronco.html

Other possible causes of bad fuel milage are.
1) Sensor faults.. pull the codes.
2) Fuel system problems.
a) leaking FPR
b) stuck FPR.. check fuel pressure.
c) Fuel tank cross flow problem. Fuel consumption rate should be the same on both tanks, if it's not you likely have the crossflow problem.

 

I'm running a 265/75/15 on the truck. I know the speedo is off because its a couple miles off from my gps. I'll try to reprogram and the other things listed and post the results...thanks guys.