11 mpg?

[jonlax]

For the past month i was on leave enjoing my explorer and driving ALOT. It has not been driven for about 7 months and prior to the 7 months it was not driven for over 10 months because of a deployment. This past summer i installed a K&N intake new 265/75/16 Duler revo A/T's, Brake pads all around, Wires and plugs, PVC valve, cleaned MAF and a new transmission. With just the tires and intake i was getting 250 miles to about 13 gallons of gas around town which is "city" driving. I live in rural bucks county so speeds are constant in the 45/50 MPH. This time i was home i was getting 200 miles to a tank unless i drove I95 which i got around 16 MPG. I also had a CEL due to a vac leak from the intake. That was fixed but with the CEL i got better MPG than with out it. I do not worry about MPG because the truck is for pleasure but with a drop that much it worries me something is wrong. I have a light foot and i do not think i have taken the truck over 2k RPM's on road which is was i drove the entire time i was home.

I have just purchased a new fuel filter and have some motor craft wires to replace the ones that are on there due to them being a cheap replacement at the time. I know Plugs can change the MPG alot because of past cars diving up to 4 MPG due to the plugs but this has gotten me baffeled to the drastic decrease. In a month and a half i will see what the problem was when i get to change out the fuel filter and some other little things. I also think i will remove the K&N due to the crappy fitment to see how she responds to that. Other than that am i missing anything? It just baffels me so anyone else want to chime in? I dont plan on doing what aldive did but rather fix this problem. Also shes a 2001 with 75000 as of the day i left 2 days ago.

 

[BradR]

That is pretty low, I just figured out my MPG yesterday, set the trip meter at half tank and ran it to quarter, did the math and i get about 15.5MPG and I drive a little heavier than you, I'll take my ex to 3k rpm from a red light if im in a hurry but very seldom do i even stay UNDER 2k. I have a 99 4dr. 4.0 ohv

What engine do you have?
What gas do you use?
Replacing the filter is a good idea, I plan on doing mine soon, with a full tune up.

Good luck figuring it out.

 

[jonlax]

The regular 4.0 SOHC.

I use Shell gas 89 octane and have been doing so since 2003 when the station was put in close by my house.

I use royal purple oil which i get for free from a friend that is a dealer.

I am thinking about changing the transmission fluid along with transfer/axles this spring when i leave from here in germany to back home in PA. She has been neglected since 2006 and need some loving.
As of right now my guess is plugs and that damn K&N BS Intake.

 

[2000StreetRod]

15 mpg with WOT

On my last tank of 87 octane my 2WD 2000 SOHC Sport got 15 mpg with multiple WOT accelerations to 5800 rpm. If I take it easy I get 22 to 23 mpg on the highway.

You've cleaned the MAF sensor and changed the PCV valve, air filter, plugs and wires so your Sport should be doing better than what it's getting. After you change the fuel filter I'd add two bottles of fuel injector cleaner to the tank.

I appreciate your service!

 

[1998Explodasport]

I have a 1998 SOHC and i too get maybe 11-12mpg. I just changed the plugs and wires with Motorcraft, and new fuel and air filter and still no change.

 

[ramren16]

That is pretty low, I just figured out my MPG yesterday, set the trip meter at half tank and ran it to quarter, did the math and i get about 15.5MPG QUOTE]

thats not how you calculate mpg at all there is no way you can get that accurate you have to fill up reset your trip meter and run the gas down, then fill up and take the miles you went on that tank then divide it by how many gallons you put back in (FILL UP) then you will get a more accurate reading the way you did it is just a bad guess since most cars fuel gauges differ to much thus just cause it says you have a half tank doesnt mean you have a half tank

 

[BADB4C]

I have a 98 sohc and I drive it very hard, for an ex anyway. I average 15.3 highway and street driving. It was around 18 until I put the 22s on.

 

[jwrezz]

With 33x12.5R15's and a fairly fresh rebuit 4.0OHV and 4.10 gears I'm lucky to get 12 now. On a tank spent in the woods it's more like 9-10. I need to do a plug and wire change, and I'm sure I'll see closer to 15 after that, but yeah. Wheelin, big tires, and a perf. tune from Bama Chips I consider it almost lucky when I hit 12MPG!

 

[jwrezz]

That is pretty low, I just figured out my MPG yesterday, set the trip meter at half tank and ran it to quarter, did the math and i get about 15.5MPG QUOTE]

thats not how you calculate mpg at all there is no way you can get that accurate you have to fill up reset your trip meter and run the gas down, then fill up and take the miles you went on that tank then divide it by how many gallons you put back in (FILL UP) then you will get a more accurate reading the way you did it is just a bad guess since most cars fuel gauges differ to much thus just cause it says you have a half tank doesnt mean you have a half tank

And yeah, that's NO way to figure MPG! Especially since most cars gauges go slow for the first 1/2 tank and then faster for the 2nd half. But yeah, you've got no idea if you're exactly on 3/4, 1/2, 1/4 etc. The only for sure is full.

 

[jonlax]

With 33x12.5R15's and a fairly fresh rebuit 4.0OHV and 4.10 gears I'm lucky to get 12 now. On a tank spent in the woods it's more like 9-10. I need to do a plug and wire change, and I'm sure I'll see closer to 15 after that, but yeah. Wheelin, big tires, and a perf. tune from Bama Chips I consider it almost lucky when I hit 12MPG!

Now if i was running your set up i would be happy with 15 but i have 3.73's and a sohc with nothing more than a K&N. Tires are 32" but they are a pound lighter than 255/70/16 wrangler A/T's.

 

[stangman82]

lol i guess my truck isnt so bad on gas lol. my 2000 sohc 4door gets 18 mpg around town. I only have a k&n drop in filter and a flowmaster 40 for mods

 

[aldive]

Have you scanned for O2 sensor function?

 

[alohamonte]

How does it idle?

When you replaced the upper intake gaskets did you also take out and clean the fuel injectors? I did. And they were filthy. Cleaned them and replaced the o-rings and mileage improved.

I also had a clogged PCV Elbow where it bends 90 degrees, which affected idle greatly. That was a dealer only part and repairing it made a big impact on mileage.

 

[jonlax]

I used a scan tool but no codes. I did not go any deeper than that due to time. March 1st i will be able to get an actual ford scaner on it and get all of the info from the computer.

 

[aldive]

I used a scan tool but no codes. I did not go any deeper than that due to time. March 1st i will be able to get an actual ford scaner on it and get all of the info from the computer.

Its not codes you should be seeking, its the FUNCTION of the O2 sensor(s).

 

[jonlax]

Its not codes you should be seeking, its the FUNCTION of the O2 sensor(s).

yeah i got that but i did not have enough time to go deeper looking into the problem. being in the army sucks since i do not have any time to look into problems. Along with usual upkeep thats neglected untill i get home things are usually really busy. The 40 cent per mile upkeep is true and seems to have caught up to me even know the SUV is not driven.

 

[trailblazer295]

I have a 02 sport with the KN filter and a new PVC valve last year. Have seen 18mpg CDN city and 25MPG highway with a full load and AC on. I saw a jump of 1-2MPG after the PVC valve on my scan gauge going down the same street at the same speed.

 

[jwrezz]

PCV, right? SO just replacing that increased MPG? Any one else have this? I don't think I replaced mine when I did the rebuild, I shook it and it rattled so I figured keep it.

 

[trailblazer295]

Ya PCV was the stock one and replaced with new. According to the scan gauge my mileage went up 1-2mpg going down the same street at a constant speed.

 

[jwrezz]

Well shoot! I'm gonna have to go pick one up and see what happens. Just 1MPG would make a difference. My last tank which was a good mix of city/hiway came out to be 11.8. Better than wheelin mileage which sinks it down to around 10 most times, but not good enough for me! Thanx for the tip!