OTG02

My 02 4.2 auto reg cab 2wd gets bout 21-23mpg on hiway and bout 18-20 round town. Rebuilt the top end both head gasket blew. Replaces the isolator bolts and upper plenum gaskets. have a si/do exhaust and the gotts mod and 265/75/16 tires. Before all this was lucky to get 12 mpg. Went through engine. Found all of Eve ports were clogged shut but 2. Replaced wires and plugs and cool pack. I guess the 4x4 are worse on gas then a 2wd lol.

TLB4

I think you forgot how to calculate gas mileage when you fixed up your top end. Might want to go check your math again. Brand new Eco Boom's barely get that kind of mileage. I call b.s. on your 13 year old truck getting those kinds of numbers.

Jbrew

I got my daughter into a 4.2L. Went through it tuned it up, but it couldn't beat the 5.4L 4x4 in mileage. She used it for a couple years though, once she started to pay for gas, she broomed it lol. Nice little truck for hauling the groceries back from the supermarket or talking the dog the park/beach. Mileage wise, yea, it had truck mileage. Looks like your experiencing that as well OP.

OTG02

Hmm. Think I just may do that. Lol. Don't hurt to check again. Lol. I'll get back to this post once refigure lol.

coolride

So far I just get a little under 14 mpg. I drive almost all highway. I don't beat it by any means but I do drive fast. At like 70 mph in 5th gear I'm running like 24-2500rpm, so its not screaming at all. I think if this truck was geared a little slower it might be better. Its like it lugs more times than not, the power range is really at a higher rpm than its geared for. I had an 88 f150 4x4 5spd, geared awesome, got like 16-17 mpg with it. Then got a 95 same truck with auto, geared so high it was a dog, got 10-11 and in 4x4 like 7mpg. I think my trucks gearing would get great mpg if I had the power of the 5.4

coolride

I had a 2000 with 4.2 5spd 2wd, that truck hit 17 mpg all the time. Sometimes a little better on a trip. I was hoping for that with this truck.
Good thing gas prices went down a bit. lol

anotherfordguy

What gears do you have? Mine had 3.55's and I was only turning about 2k @ 70mph with my 4r70w. The 4.2 is similar to the new 5.0 in that it loves to rev. Anything below 2-2.5k and it'll lug some, it doesn't make peak torque until 3.4k rpm's and doesn't hit peak hp until 4800. Anytime I had to give it a decent amount of gas it always had to down shift. My grandfather's 79 F150 4x4 Supercab with the 6.6L V8 with around 479k miles (yes original motor, 3rd gear was rebuilt on trans) got the same mileage around town as my 4.2 RCSB.

coolride

I'm not sure the gear ratio. Must be 3.55 at least. It runs 2400 at 75 mph, I looked again yesterday. It has its best power at 3500 to 4000 rpm.
My 95 with the 5.0 automatic was like this, just lug around, burning up fuel. Not really burning rubber though. lol No power for that

ninerhb

Another 4.2L 2WD auto here getting much better mileage. Driving around town I get about 15-16 on average. The few times I do longer highway runs, I sit around 20mpg, pretty even. Granted, it's a short bed, short cab, so it's the smallest F150 you could buy.

65comet

My 98 4.2 2wd auto gets 22 on the highway. Nothing modified. So, yes they can do that. But that is "true" highway. One mile to the interstate with only one stop sign, get on, drive 66 miles to work at 55 mph. Get off and less than a mile to work with again only one stop sign. My wife gets about 13 around town, but she only knows Full throttle, till you have to slam on the brakes. Repeat.