I am a Jeep ADDICT, my wife drives the F150. My Jeep is alot of things but gas friendly it is NOT. It has the aerodynamics of a brick and an engine designed for torque. I get 11-12mpg if I'm lucky on my 04 Wrangler Unlimited.
Would i drive anything else?? Hell No!!!!!!! If I wanted fuel economy I'd by a Geo

 

don't buy a Jeep for fuel mileage. I don't think I've ever gotten 18mpg


jeep front end ---- |

F150 front end --- /

 

My '02 SCab was only getting 12.5-13 mpg for the first 8 months I owned it (bought it used). Then I got some intake cleaner and cleaned the intake and throttle body. Within a week my mileage started getting better. I cleaned it again and just this week I got 17 mpg on a road trip (never topped 15 before).

 

That's very impressive! How many miles on the engine, and which type cleaner did you use?

 

Aerosol intake/ throttle body cleaner. I read somewhere here that carb cleaner might harm some of the plastics used in the new intakes, so just to be safe I made sure I got the stuff labeled for throttle bodies. I also read a thread here somewhere with pictures of a complete disassembly, etc. although I didn't go that far. I took off the air intake tube and a couple easy lines and just sprayed the crap out of the inside, trying not to get overspray all over the engine or exterior paint.

The truck is an '02 with a 5.4, bought it with 37K miles and it now has 59K.

 

That’s a byproduct of consistently using crappy gas. The MAF (meter or sensor) gets out of wack and throws off the stoich (14.64:1) A/F ratio in closed loop. Once that happens fuel economy is down the drain.

 

Maybe that is what mine needs. 01, 5.4 SC 2wd, w/ 114000 miles. My 1st tank w/ early am easy interstate & some mixed w/ city driving, driving easy, shifting at 2-2500 rpmssss returned *#%*!! 12 MPG. I expected that if I drove it hard, but not grandmawing around. We got 12 mpg w/ my friends 01 1500 2wd pulling a race car on a open trailer as hard as we could go. My salesman talked to the prev. owner & she did not know if they did the plugs @ 100k mi. Truck runs smooth & pulls hard(for a stock truck). I guess I need to do a search on the plug change procedure.
I have already added an Airforce One intake, Magnaflow 2/1 Y pipe, Magnaflow 3"SI/2.5DO w/ duals out behind the wheels.
The exhaust helped power, but the Airforce One could really be felt, especially at tip in or low rpm. The exhaust sounds sweet too. I got 14 mpg on my second tank when I filled up today. Next tank w/ the mods should see better mpg, I hope. A steady diet of Chevron gas may help also as I do not know what they used. Any plug change tips or Ford rookie hints are welcome!
later

 

Yeah, MPG is not good when you drive a TRUCK. Currently my computer says 13.3 mpg. I use 87 octane, and drive like a raped ape. My daily commute is 52 miles round trip. Just installed the 1745 tuner yesterday, havent noticed a difference in mpg yet, but wow what a difference in performance!
People buy the 4.2, 4.6 thinking they will get better fuel economy. If they do, its negligible.

 

Since the only thing that goes over the MAF is air, please explain how crappy gas makes the MAF go out of whack.

 

My Grand Wagoneer should net me low 20's when I'm done with it. I do manage to pull about 14 on the highway with my V8 CJ5.

 

Cheap gas / good gas could possibly come from the same base stock; what sets them apart is the additives. The PCM uses feedback from the upstream O2 sensors to constantly adjust the A/F ratio to 14.64:1 in closed loop. (80% throttle or less) Bad (clogged) O2’s = improper feedback.

 

Absolutely true! MPG is affected much more by vehicle weight and aerodynamics than engine size. This is evidenced not only in the case of the F150, but also by the early '70s Corvettes. The difference between a 350 Corvette and a 454 was only about 1-2 MPG, and much of that could be accounted for by the weight difference (about 400 lbs. if I remember correctly).

 

We are paying over $1 dollar per LITRE here in ontario canada now. There is at least 3L in a US gallon , so we are paying well over $3 a US gallon.

I drive about 500 km a week, and it is costing me $70-80 per week! Just to drive to work and a little bit on weekends!

Filled up from just below half the other day and it cost $63 CAN for just over a half tank!!!

i just changed plugs and fuel filter, hoping it will get better. I might change 02 sensors too.

 

I just bought an 05 Supercrew XLT, 5.4, 2wd. It has 3.55's in it and I just topped the tank off and calculated 13.9, about 70% city miles. Now this truck just turned over 250 miles, I know it will improve. I traded a 03 Tacoma extended cab with a 3.4 and an automatic. I never got more thah 17 with that truck. Why have a compact truck and get mileage like that. If you want 30mpg...........buy a Focus.

 

$135? youre upset about that? Try close to $400.... $2.55/galon here. 140miles total back and forth to work each day