gas mileage

[darrbonn]

I have a 2001 sle and I find the gas mileage terrible. Is there something I can do to make it better. I just bought it a month ago.

[Headbolt]

So what are you getting in the MPG category that you think is terrible? I'm searching the forum for suggestions on what might be ailing my '99 in this department. I haven't been driving it much in the past few months so haven't checked the mileage as often as I would normally. Since the prices took off I've been checking and am getting around 11 MPG. OUCH!! It runs fine with no indications of a problem. I drive 12 miles to and from town at around the posted speed of 45 MPH and some highway stuff at 65MPH. Looking for some suggestions. I'm thinking maybe a temp sensor, but which and where? Thanks.

[DRW1000]

Do either of you have the CEL on? 11 MPG sounds low.

I get about 21 Mpg for my 99. This is highway but often in stop and go and not really driven overly conservatively. I am using imperial gallons which are about 15% larger. (I think).

A CEL will most likely cause a vehicle to waste fuel due to the PCM trying to compensate.

Ensure that the van has the filters changed. Drive with the Windows closed (use air). Synthetic motor oil might help a bit. Ensure that OD is not shut off. I also removed the rear seat and am about 80 lbs lighter.

[Headbolt]

Originally Posted by DRW1000

Do either of you have the CEL on?
A CEL will most likely cause a vehicle to waste fuel due to the PCM trying to compensate. Ensure that the van has the filters changed. Drive with the Windows closed (use air). Synthetic motor oil might help a bit. Ensure that OD is not shut off. I also removed the rear seat and am about 80 lbs lighter.

I've got no CEL. It runs like it always has and no indication of a problem other than I'm stopping for fuel A LOT. The air filter was changed just about three months back. I used to get 20 MPG U.S. without a trailer behind. With a loaded trailer it woud drop to 14-15 MPG U.S.. The tranny was repl;aced back in May and haven't checked mileage since. Mayhap the mechs left something undone or broke something while replacing. Nothing obvious as I have poked around for loose/dangling connections. The tail pipe doesn't seem to be overly black do to rich mixture. Has good push as far as exahast too. Just hoping someone on here has had this happen and found the problem and will pass it along. I don't have the equipment to properly troubleshoot these things. Trial and error can get expensive and be a long drawn out affair. Thanks for the reply.

[DRW1000]

At highway speeds (100 Kph or 63 MPH) what are you reving at?

Perhaps it is not going into overdrive. Grasping at straws here but anything is possible.

BTW in my last post I meant that the van is 80 lbs lighter. Not ME!!!

[road_rascal]

In my '01 I get about 15-16mpg in stop and go traffic and maybe 20-21mpg highway. This is using madated $hitty MN ethanol blended gasoline.

[floridatgp]

I have seen bad O2 sensor that wouldn't set a CEL but was dropping mpg by almost 30%. need to scan and see if it voltage bounces betwee 0.9 & 0.2 volts or so, every few seconds

[cycleguy55]

Originally Posted by darrbonn

I have a 2001 sle and I find the gas mileage terrible. Is there something I can do to make it better. I just bought it a month ago.

One of the fellows I work with had similar problems with his 1996 Windstar, and his shop tracked it down to a vacuum leak. I wish I could provide more information, but he had it done by his dealer (under warranty, I believe).

As a start, I'd look at any of the lines which may have been close to where they were working when they replaced your transmission.

FWIW, I have a 1998 Windstar and average about 25 MPG combined (imperial gallons - equivalent to 20.8 miles per U.S. gallon) and up to 30 MPG highway (imperial gallons - equivalent to 25 miles per U.S. gallon). I just had a trip on the weekend, and the first leg of 560 km (348 miles) was an average of 28.4 miles per imperial gallon, or 24.0 miles per U.S. gallons. That included a small amount of in-town driving, but mostly highway at 110-120 km/hr (68-75 mph).

[DRW1000]

Vacuum leaks should cause the CEL to illuminate.

At 100 KM/hr (63 M/hr) I was reving at about 1800 RPM in 4th. When I turned off OD I was reving about 2200 RPM.

[Headbolt]

I guess I'll have to get "down & dirty" here and crawl under the beast. I've checked all that I can see on top and nothing obvious. I think I'm running 2200 in O.D.. I believe that is what it has done since I've had it. I'll have to pay closer attention next time out which will be Friday. I've got the code reader, but it does no good unless there is a CEL or so I'm told. I figured if the 02 sensor(s) were in trouble I'd get a CEL. Maybe not, though. Will check further and watch here for any more possibilities. Thanks for the replies. Hope I'm not being out of line using this thread. Just seemed to fit my needs without cluttering the place up for the next person doing a search.

[DRW1000]

I don't know what the rules are but in general if your posts are on the same topic as the thread starter then it makes sense to continue it. So I think your posts are fine here.

Actually a code reader can detect pending codes. A pending code is a code that showed up once in the last 20 starts but has not illuminated the CEL. This accounts for minor glitches.

If you think you are reving at 2200 at about 60 MPH then perhaps your transmission is not going into overdrive. This would impact MPGs significantly.

[rodeo02]

You should be averaging somewhere in the low 20mpg range with a 1999+ 3.8L windstar. First thing to check would be tires. Worn, noisy, under-inflated tires can knock a few MPG's off real easy. A heavy foot or a loaded down van will get you mid to high teens for MPG's.
G/luck
Joel

[Headbolt]

My wife had to make a run today so had her check RPMs at 60 MPH. She says it is doing between 1800 & 1900. The tires are new this spring and inflated to 35 PSI all around. I still haven't gotten under it for a closer look as I have other irons in the fire. Will try for tomorrow. Sounds like the fuel is going to do another leep do to the weather in the gulf again. I'm not real heavy with the go pedal, but at times you have to give it a little extra just so you don't get run over around here. I wish I had watched a little closer so as to pin point when it started doing this. I had a "no start" condition a while back that I haven't had a reccurence of. I think I posted on that around the end of June. It wouldn't start, but after about an hour of trying off and on it just decided to go again. Might have been when this fuel consumption thing started. I'll have to see if I can dig up my slips and get a better indication. I always write the mileage on the receipt when I fill.

[wiswind]

Several things that I would suggest.....I have a '96 3.8L windstar....

1. Short trip runs (the 12 mile drive is short) will result in low fuel economy...as much of the trip, the engine is warming up....and "stop and go" is a really variable term.....as in how much stop and for how long......how much speeding up & slowing down.....and so on.

2. The car will get it's best fuel economy driving at a steady speed.....and of course.....hilly roads are not going to make your mileage go up......

3. Keeping the car tuned up with new filters, etc.
The spark plugs are good for 100K miles...unless there is something wrong with the engine to cause wear to them. You want to replace them with ONLY the correct Motorcraft Double Platinum plugs for your year. Other brands will not be as good.

4. Periodic treatment with a good fuel system cleaner....such as Chevron Techron (2 "treats up to 10 gallons" bottles for the standard 20 Gallon tank) will keep the fuel system....as in fuel injectors, and intake valves.....etc clean. I still needed to to a manual cleaning of the inside of the "cap" on the spray end of the fuel injectors....but that was on my '96 at over 135K miles.

5. Part stores love to sell oxygen sensors. If you do replace them.....I would install....ONLY the correct Motorcraft brand oxygen sensor for your year. From what I have read....you would only need to replace the "upstream" oxygen sensors......the one that is in between the catalytic converter and the engine. The upstream sensor is the one that is used by the computer for fuel mixture. The "downstream" sensor is used to monitor the catalytic converter to make sure that they are working. Unless you have a failure code.....they should have no effect on fuel economy. Oxygen sensors switch between lean and rich....as indicated in a previous post telling you of the switching voltage. As they get older....they switch slower. The computer monitors the switching speed.....and if they get too slow.....You will get a CEL....telling you that the oxygen sensor is switching too slow. The upstream sensor will switch faster than the down stream sensor.
Oxygen sensors are good for a LONG time.....rated for 100K miles.....and beyond. Auto part stores like to tell you to replace them at 50K miles and sooner. Maybe that is correct for some cars....but does not seem correct for the Windstar.

6. Good tires....kept at the correct pressure. I keep mine at 35 PSI. If you tend to neglect tire pressure......MANY people do.....I have seen valve stem caps....that you get for a given pressure....say 35 PSI..... If the pressure is OK.....the end of the cap is green.....If the pressure is low.....the end of the cap is RED. I do not know how well they work.....perhaps someone on here can let us know.

7. Dragging brakes can be an issue. Seriously warped rotors (disks) can touch the pad on each revolution. Pulling to one side is an indication of significant brake drag on one side......but there are lots of things that can cause the car to pull to one side. Wind, slope of the road, tires, suspension parts.....etc.
Rear drum brakes are a common source of brake drag. When doing a rear brake job....replace all the hardware.....(springs and such). They sell "hold down hardware kits" for disk and for drum brakes. Not expensive and very worthwhile.

8. Overdrive. Using my '96 as a point of reference....The shift lever on the steering column has a button on the end. With the engine running.....press the button. There should be a O/D light come on.....toward the end of the shift lever......near the button. When the O/D light is ON.....the transmission is locked OUT of overdrive. So if the light is ON....press the button to turn it off. If you cannot get the light to come on.....then there is a problem. If the O/D light is flashing when you are driving.....it is telling you that the transmission electronics have detected a problem.....think of a flashing O/D light as a "check transmission light"
If you are cruising along at 50 mph, or so.....and you press the O/D button.....you should be able to feel the engine rev up...(and the tach will indicate that), as the transmission "downshifts" into 3rd gear. Press the button again to re-enable overdrive (4th gear) and you will feel the engine slow down (and you will see the RPMs drop on the tach).

9. This is hard to do.....Drive slower. I find that I get better fuel economy on the highway if I set the cruise control for 65mph (in a posted 65.....NOT a posted 25), versus 70mph or faster ....which is what most traffic is doing. I find that I am one of the slowest cars on the road at the speed limit....to 5 above (and I know my speedo is correct within a MPH or so)....After years of blending in with the general flow of traffic......and noticing that the general flow of traffic has gradually increased over the years.......it is hard to ride along in the right lane with almost everyone passing me. I mean....I normally have LOTS of people passing me....but find that slowing down even more....but at the posted limit.....saves fuel.

This is a very good thread....given what gasoline prices have been doing.
Take note that the "oxygenated" AKA reformulated gasolines will give you slightly lower fuel economy.

[12Ounce]

Comparatively speaking, Georgia always seems to have fairly low gasoline prices. Don't know why ... perhaps it has to do with all the pipelines and railways that come through Atlanta ... and fairly low state add-on taxes. Always glad to get back to our gasoline prices after an out-of-state roadtrip.

In Sept 2001, we were on vacation in San Francisco. I was shocked at the absurdly high gasoline prices ... about $.60 more per gallon than what I paid back home ... took a photo of a '76 gasoline station's posted prices to show everyone back home. (I just went through my digital photo album to make sure my facts are correct.)

$1.939 per gallon regular. $2.139 per gallon premium. "Insane", I thought.

Four years later and Dang! ... I wish I could find it at that "absurd" price anywhere today!