MPG gets worse - Ford Forums

jherrer · 03-05-2007, 18:50

I have had my 2002 Mountaineer since around august 06. When I first got it it said that it was getting 14 mpg...later i kept driving and on average it was around a 13.6 mpg...& Ever since this year began I am averaging about 12.3 mpg...What the heck do you guys think is going on here. I don't have a heavy foot so I know it can't be my driving, i've been driving the same way since I got it. I drove on the highway today and it went up to 12.5 mpg...

Could this be a bad sign of something else? Spark plug problem, would they need to be replaced or would all of that been done at the dealership before i got it?

Any hints or help would be greatly appreciated.Thanks for your help.

**Big Block Ford** · 03-05-2007, 21:46

If this is a petrol vehicle are you using different fuel?.

Somtimes lower octane fuel ,though cheaper can actually deliver lower milelage. Some of the newer engines with knock sensors will advance timeing to just run just below pinging so if you use cheaper low grade fuel then timing will be retarded back to allow for that.

Other possibilities are tyre pressures lower, brakes binding, air filters dirty.

jherrer · 03-07-2007, 20:10

Big Block Ford, thanks for you advice, i'll take a look at the filters and make sure that they're all clean.. The tire pressure might have something to do with it. I live in ohio and since it got colder I think the tire pressure might have gone down ( not completely sure, i think i've heard something about that happening.)...

I don't think that the gasoline that i use would be a problem, i use regular unleaded but i believe that this was the same type that was used by the owner before me.

If anyone else has any more ideas, please let me know.

thehamstack · 03-08-2007, 07:34

Well there is certainly nothing wrong with checking your filters and tire pressure etc., as a matter of routine maintenance. The drop you are experiencing may be normal, tho. In many areas, oxygenated fuel is mandated by the epa during the winter months to reduce emissions. Also, I imagine you let your rig idle some to warm up before you take off. These items will cause a noticable decrease in mileage.

The point is, keep in mind you may not have a problem.

Johnny Mullet · 03-08-2007, 07:55

Get your tires filled with Nitrogen so you will not have to worry about air pressure ever again. I put nitro in both my vehicles and have not added a pound of air in 5 months.

And like BBF said, Air filter, fuel filter, injector flush, etc

jherrer · 03-09-2007, 20:09

thanks for all of your replies. They were all very helpful and taught me new things. Again, thanks for your help.

jherrer · 04-01-2007, 19:45

Hey again, thanks for the help. I cleaned out the air filter and I think I might've had the O/D in OFF, but I'm not 100% sure. Anywho, the mpg went up to 14 mpg. So thanks for the help.

But damn, i heard of someone who gets 18 mpg on his mountaineer. How the hell would you pull that off.

**Big Block Ford** · 04-01-2007, 22:45

Thats good news.

Higer tyre pressures can help your mpg. If you have put wider tyres on your machine then that can cause extra fuel usage too and yes use your O/D too.

I guess if you drove it like a real granny then you would get better mpg but wheres the fun in that lol.

Its great that you reposted to let us know how you got on.

HappyExplorer · 04-13-2007, 22:52

Definately check your oil. May sound stupid but make sure your oil is clean/new/at the right level. Grime buildup in an engine can do this, so can using lower grade fuels. Go to your nearest auto parts store and get a "Fuel Injector Cleaner". (make sure it has a lubricant in it so it doesnt dry out your car) and it should clean Carbon buildup along with other things.