Gas Mileage

[peterbrown77]

I don't know that I actually need O2 sensors, I just know that I need better mileage! I'm just going through things one-by-one. I cannot live with a 15mpg car and I'm pretty disappointed with my 'new' 2000 in this regard. I just don't understand how I can be so far off the claimed 16/21 EPA. The thing runs great too, so I am not expecting to find some silver bullet like a bad injector.

 

[tdhess]

I feel your pain. My wife just got a 2005 Explorer XLS Sport. It has 3900 miles on it and it only gets 12 mpg. My 2002 F-150 4.6L gets 16 mpg city.
The explorer is going into the shop Saturday!

 

[peterbrown77]

I have been doing some testing and was going to post a summary in a while after I've gathered some more info.

I simultaneously cleaned the mass airflow sensor (didn't look particularly dirty, and I know there's a 'burn-off' cycle it goes through) and installed a K&N filter ($46 at AutoZone).I'm pleased to say that I've gotten it up to 17.2mpg on average over the last 3 fills. I also changed 4 of the 6 plugs - those last two are a mother. The gap is supposed to be .054", and I measured the old plugs at about .090".

Next on my list is to remove the air silencer horn from the air box. I've read of some posts where people have drilled 1" holes in the box too, but I don't think that is very effective. Air at velocity moving through a hole in such a thin wall is completely turbulent and the effective diameter is probably more like 1/2". If the length of the hole was 2 or 3 times diameter and the ends nicely rounded, it would be a different story. Anyway, I'm going to enlarge that opening next and try to find some of this Amsoil PowerFoam I've read about and shoot that in too. After that, I'm probably out of 'cheap' things to do.

Is your XLS an 8 or 6?

Regards

 

[Buzzsaw]

I did an airbox mod and K&N hiflow filter on my 01 Sport 4.0 SOHC. First I just removed the silencer which essentially doubled the amount of airflow and gained just a bit of performance, just enough to tell something positive had happened. I then thought I would cut another hole beside of that one about the same size and double the airflow again. After doing that I noticed that I had lost some low end torque performance. Couldn't really feel any high end gains just a noticable loss at low end. I glued and patched the last cutout back in place and went back to the first mod setup and regained the low end. So I would advise to try adding a little at a time to see if you get any adverse effects before hacking up the entire box with holes that would be hard to repair.