poor gas mileage!

[Chris Joyce]

I went on a trip this weekend and I got about 200miles to a full gas tank. That's not so good. I've already changed the fuel filter and I had correct tire pressure. What else could I do to help my truck?

 

[James FreemanJr]

Last time you had a check up/tune up? Might be due. I'm in the same boat also (getting about 15mpg) but I also have 88K miles on my truck

 

[Rodger Tellefson]

A Cold Air Intake of your choice, an exhaust that sounds good to you, and most important an SCT XCalibrator2 from Wayne Foy at Hypnotic Illusions a site sponsor. We got one with a program for better gas milage, and got 28 mpg doing an avg of 60 mph & 21 mpg doing an avg of 80 mpg; both of those are all hwy driving. We have a manual tranny with 3:73 LS rear end and 235/70/16 tires. Give Wayne all of you specs, and he'll give you a program for better gas milage.



edit: We have over 100k on our ST. Remember to clean the air filter (or replace with CAI), the Mass Air Flow Sensor, and the Idle Air Control. Also, change to a good synthetic oil as well; I went with Royal Purple, but Amsoil & Mobil 1 are also highly recommended here.

 

[Chris Joyce]

I've got 51,000miles on it now. My MAC intake is comin wednesday.

 

[OFF TRAC]

yikes, 200 miles on a full tank of gas 'aint good.



I go about 243 miles on just a smudge over half a tank of gas on my ST and it's got 105,000+ miles on her doing 75-80mph



I have a K&N drop in filter, removed the air silencer in the filter box, custom made exhaust with dual glass packs, dual tip platnum spark plugs, tornado air intake insert, use lucas fuel stablizer on every full tank of regular unleaded, mobil 1 syn-tec every oil change, proper air pressure on all 4's and 4.10 gears.



IMO check your spark plugs,wires and air filter then i would take it in if still under factory warranty or to a service shop ypu trust/is recommended and have a diagnostic done on it.

 

[Scott Tanner]

Something must be wrong with the ST. i get better milage pulling my 5000 lb rv! Look into doing the plugs/cap/wires/aircleaner first, then i would take it to a shop and have a diagnostic done on it, looking at the sensor outputs, and the exhaust backpressure. Sounds like it might be in a 'limphome' sort of mode, and not managing the air/fuel correctly. 200 miles to a tank is less than 10 mpg. JMHO..

 

[Andy G]

I typically get about 20MPG. The only mod I have right now is a MAC intake. (2001 Job 1 4x4)



But, my mileage did drop to about 13MPG WHEN MY CATALYTIC CONVERTERS STARTED TO PLUG UP.



If you notice any power loss at high RPM, that is about the only other symptom. It may or may not trigger a CEL, mine did not.



My cats failed at 78K. Warranty on Emissions control equipment is up to 80K.



I would definately not rule out this possibility.

 

[biznaga]

If you look at the log for all 8000 or so entries it appears the average is about 15mpg. That is ewhat i set, except in town it drops to about 11 or 12. But on highway I get up to 17, so my average is right at 15mpg, like the chart average.

 

[WXMotorSports DecalsPartsAccs]

Yikes. I avg. 400 on the highway and that includes several mtn passes.

 

[Scott Tanner]

that's what i meant to diagnose by the backbressure, as andy said the cat's might be on the way out. i get about 16-19 around town, and i've gotten 23 on the highway before...

 

[james smith 4]

Thats only about 8 mpg, you should get at least 340 to 360 miles to a full tank. I'd start with a complete tune up and check for any codes from the computer.

 

[Gypsy me]

Try using cruise controll if you have it. Over the road I drop my air pressure by a 1/2 lb each tire. I too get on the average 24 mpg stock, over the road.

 

[Chris Joyce]

Thanks, I will look into getting plugs and wire asap. Then just ask my mechanic to do a diagnostic check on my truck? Just tell him that I get poor gas mileage.

 

[Scott Tanner]

Not to Dis your mechanic, but i would consider taking it to a good ford dealer. they have the specialized equipment to quickly and accurately diagnose the issue. Make it be known to whoever works on it, that you are not interested in changing parts in an attempt to locate the issue. There are still parts changers out there, even at dealerships. When they come back and say you need a new 'blah blah' part, let them know that if it does not fix the issue, then you should not have to pay. I use this approach and has saved me from part changers more than once. With your mileage, the issue should be fairly obvious. Are you putting in 21 gallons on a fill up? if it will take in the mid teens, there may be an issue with the filler neck, or vapor cannister system... ket us know what you find... JMHO

 

[Chad Merry]

I get 15mpg if I am lucky. 02 4x4 K/N Filter custom made, new plugs, Diablo Chip with 2 programs, but I also have 285/70/17 tires. Maybe I should go with the SCT tuner instead?? And is there a way to take the insides of the cat converters apart?

 

[Andy G]

It took a dealers analysis to figure out my cats were bad. You won't pay for it either if the cats are bad and you are under 80K.



chad-- do you mean to check for problems, or to just remove the catalyst?



If looking for problems, the dealer has got a computer running into what looks like a dyno unit, and they are watching computer behavior and sensor reports while stressing the motor. Most mechanics do not have this capability. That is really the best way to identify a problem with cats. They can also pull an o2 sensor and place a pressure sensor there and check the backpressure level.



As far as removing the catalyst, you may not pass emissions control anymore, but I know people who have taken the clamps off of their pipe, pulled the cat down and broke all of the material out with a piece or rebar. Then suck it out with a shop vac. I would not recommend it.



RandomTechnology makes a pipe that replaces the Ypipe and gets rid of the pre-cats. They also make a main pipe, with a highflow cat unit on it. This is a great exhaust mod.

 

[David Jones 4]

I average about 280 miles a tank. Thats mostly city driving and stop and go. Since I'm in Hawaii it's hard to do any real "freeway" driving. WHen I do I'm over 300.

 

[Scott Tanner]

BTW, Rascus, why does Hawaii have an 'Interstate' highway? :lol:

 

[Derick Cardenas]

On my stock ST. I average 440 kilometers full tank or about 270miles. Is that bad? i do city drving in manila philippines which is traffic all day.

 

[Andy Pelletier]

Too add to the poor MPG rage...I've been monitoring mine the past two months and I have yet to get over 250miles to a tank. This past weekend was as trip from CT to MA. It was all highway and I set my Cruise control at 68 mph....again...barely made it to 250 miles. I have an '01 with drop in K&N, Custom Gibson exhaust and running 265 Revo's...I'm bringing it in for the 60K tuneup on wed, and i'm goign to have them do the plugs...I'll let you know if the tuneup has any affect to my mileage.