Gas mileage down the drain???

[01BaRanger]

Hi guys, I drive an 01 ranger XLT 4x4 with a 4.0, it's got around 108k miles on it, and my gas muscle age seems to have suddenly gone down the drain, I was getting 200+ miles on my little 14 gallon tank, now I'm lucky if I get to 150, my driving habits aren't bad at all honestly, and I have given it a new fuel filter, spark plugs, and air filter. Only thing that isn't Fresh is the oil filter and that will be done this week, and I'm still gettin worse an worse mileage, you guys have any ideas? Any an all help is appreciated!

 

[bbbb51]

I get the same lousy mileage with my 02 4.0. I would like to know what to check also.

 

[Mark_88]

Check for codes...tire pressure...and what "type" of driving do you do? Highway and City can make a big difference...and maybe tell us what size tires you are running...

I get the same lousy mileage with my 02 4.0. I would like to know what to check also.

If the truck in your avatar is the truck in question...how much wider than stock are your tires/spacers? I would think a wider stance and wider tires will affect the performance considerably...did your gas consumption go up after installing those tires/spacers or was the truck like that when you bought it.

I know the 4.0 is no miser when it comes to gas, but it should be getting around 20 mpg hwy driving...from what I've read from other members.

 

[Robalo67]

Same situation and would love to know why

I'm getting maybe 12 mpg on my 01 ranger 4.0 and from what I understand it use to get great gas mileage as I bought from a friend.He ended up taken the front driveshaft out thinking that would help it didn't.

 

[RonD]

After 1998 Ford started using Returnless fuel delivery, so fuel pressure runs at 65psi in the fuel line from the tank to the injectors.
Any small leak would effect MPG, if possible I would get a fuel pressure gauge and check if pressure drops and continues to drop after engine is shut down, indicating a leak.

O2 sensors use a chemical reaction to test for oxygen in the exhaust, so they do wear out, and they wear out towards the Lean indication, which tells the computer to run engine richer, there would be no code because the O2 sensor is working, it is just causing a richer mix, so MPG goes down.

MAF(mass air flow) sensor plays a big roll in fuel/air mix, and these do get "dirty" over time, but are easy to clean.
http://www.therangerstation.com/tech_library/CleanMAF.html
Also make sure air plenum(air tube from MAF to Intake) is tight and crack free, the MAF sensor only works well if ALL air coming into the engine passes it, an air leak allows unmetered air into the system.


Fuel injected engine can't use a standard Choke Plate like a carb did, so to start and run a cold engine using fuel injection you need something to tell the computer the engine temperature, so the computer can richen the mixture until engine warms up.
The ECT(engine coolant temp) sensors is what is used, this is a TWO wire SENSOR that looks similar to the ONE wire SENDER that is used for the dash board temp gauge.
The ECT sensor is a simple resistance sensor that tells the computer the engine temp.
If engine runs rough cold but fine warm then this could be the issue, or if engine runs fine cold but rough warm this could be the issue.
But easy to test with an OHM meter.
ECT sensor acting up would usually turn on the CEL, but not always.

 

[Mazda]

Change your O2 sensors and you will get your millage back. Unfortunately there I think there are 4 on your motor so it's a big expense, about 200 bucks depending on where you get them from and if you do it yourself. A lot more for a shop to do it.

I only have one on my little 94 2.3 so it wasn't bad.

 

[RonD]

On a V6/V8 you should only have to change the "upstream" O2 sensors, on the exhaust manifolds.

The "downstream" sensors are for testing if the catalytic converts are working, so wouldn't effect MPG

 

[01BaRanger]

Check for codes...tire pressure...and what "type" of driving do you do? Highway and City can make a big difference...and maybe tell us what size tires you are running...



If the truck in your avatar is the truck in question...how much wider than stock are your tires/spacers? I would think a wider stance and wider tires will affect the performance considerably...did your gas consumption go up after installing those tires/spacers or was the truck like that when you bought it.

I know the 4.0 is no miser when it comes to gas, but it should be getting around 20 mpg hwy driving...from what I've read from other members.

I drive mostly city but it's a distance of like two miles twice a day....and even my hwy mpgs went down the drain, a 60 mile trip costs me a quarter tank

 

[01BaRanger]

And I cleaned my MAF a month or so ago it wasn't even really dirty then, and this may be a noob question but what do you mean by check for codes? None of my dash lights are coming on or anything if that's what you mean.

 

[adsm08]

On a V6/V8 you should only have to change the "upstream" O2 sensors, on the exhaust manifolds.

The "downstream" sensors are for testing if the catalytic converts are working, so wouldn't effect MPG

Theoretically this is true. However I have recently learned that the downstreams can affect fuel economy. Ford just recently released an update for the ecoboost F150 because they found some of the running/cat problems were because the catalyst monitor wasn't completing.


I would still only do the upstreams.





How is the trans fluid? Crappy dirty trans fluid can also hurt fuel economy. You also have to watch the ethanol content in your fuel. I find it can cause me a pretty good MPG swing as the content changes.

 

[Mark_88]

And I cleaned my MAF a month or so ago it wasn't even really dirty then, and this may be a noob question but what do you mean by check for codes? None of my dash lights are coming on or anything if that's what you mean.

Yes, checking for codes reads anything the computer spits out indicating that there is something out of specifications (spec). If you are not getting the CEL on you may still have codes that could tell you something is not quite right.

All that is mumbo jumbo to me to be honest...my carb system runs without a computer and I've never had to check for codes (except on my Suzuki, but I had a shop do that at the time)...there is, however, a section in the Tech Library that goes over it...and you can get your codes read by some auto parts dealers (I think PEP Boys and a few others have been mentioned).

It isn't really rocket science but it may take you a bit of practice and patience...and some reading on the code meanings...but you will come to understand your truck much better and become more proficient at troubleshooting these things.

In some cases the codes are a bit misleading as it may throw two or three...and referring to different parts of the system...but these are related to each other in some cases where one reads out of spec so the others will also...so if you run into problems just post the codes you are getting (if any) or search on them...

I see codes posted on here pretty often and the questions have been answered dozens of times by the more knowledgeable members...so the answers are here already in most cases...

If you've never changed an O2 sensor then it may seem a bit daunting at first but it is actually quite simple...unless things are rusty...like a good exhaust system should be (lol)...

 

[01BaRanger]

Theoretically this is true. However I have recently learned that the downstreams can affect fuel economy. Ford just recently released an update for the ecoboost F150 because they found some of the running/cat problems were because the catalyst monitor wasn't completing.


I would still only do the upstreams.





How is the trans fluid? Crappy dirty trans fluid can also hurt fuel economy. You also have to watch the ethanol content in your fuel. I find it can cause me a pretty good MPG swing as the content changes.

I actually just put tranny fluid in, I didn't look or smell wierd when I checked it last week, just low, and what exactly do you mean by ethanol content? As in what I use at the pump? Cuz I just use the regular stuff, all I can afford.

 

[01BaRanger]

Yes, checking for codes reads anything the computer spits out indicating that there is something out of specifications (spec). If you are not getting the CEL on you may still have codes that could tell you something is not quite right.

All that is mumbo jumbo to me to be honest...my carb system runs without a computer and I've never had to check for codes (except on my Suzuki, but I had a shop do that at the time)...there is, however, a section in the Tech Library that goes over it...and you can get your codes read by some auto parts dealers (I think PEP Boys and a few others have been mentioned).

It isn't really rocket science but it may take you a bit of practice and patience...and some reading on the code meanings...but you will come to understand your truck much better and become more proficient at troubleshooting these things.

In some cases the codes are a bit misleading as it may throw two or three...and referring to different parts of the system...but these are related to each other in some cases where one reads out of spec so the others will also...so if you run into problems just post the codes you are getting (if any) or search on them...

I see codes posted on here pretty often and the questions have been answered dozens of times by the more knowledgeable members...so the answers are here already in most cases...

If you've never changed an O2 sensor then it may seem a bit daunting at first but it is actually quite simple...unless things are rusty...like a good exhaust system should be (lol)...

Well thanks! And yeah no lights on my dash are on, so I'll look around and see about finding a shop that will look and see I there's any codes she's throwin out, and I'll see about that pressure gauge too, I don't assume I have any leaks cuz there's never an drip spots, and there isn't any whistling is whining or anything when I open the hood while running, that's partly why I so confused lol I have no idea what's the hell is wrong, or went wrong I should say. Thank you this is all very interesting and helpful! I never gave the O2 sensor a thought, partly cuz I have no clue how to get to it, I'll see what I can find in my Haynes repair manual.

 

[tmcalavy]

Do all the tuneup stuff, then get a voltmeter and learn how to test your sensors that tell the computer how to tweak/control the engine. Pull the codes to see if there is a hard fault set in the memory. If you're running regular old 10% diluted gas (10% ethanol) that will cost you 3-5 mpg as opposed to real non-diluted gas. There are websites that tell you where you can get real gas in your area. Some places are running E-15, up to 15% ethanol/gas blend...which sux in terms of mpg.

 

[Mark_88]

Do all the tuneup stuff, then get a voltmeter and learn how to test your sensors that tell the computer how to tweak/control the engine. Pull the codes to see if there is a hard fault set in the memory. If you're running regular old 10% diluted gas (10% ethanol) that will cost you 3-5 mpg as opposed to real non-diluted gas. There are websites that tell you where you can get real gas in your area. Some places are running E-15, up to 15% ethanol/gas blend...which sux in terms of mpg.

Which means we are getting a double whammy when they charge the same or more for diluted gas and get less from what we put in out tanks...

Tanks Big Oil...TANKS MUCH...

I've been noticing a drop in my mileage also and have gone over and over the basics...but I also keep pretty good records of how many miles per tank (on a monthly basis usually)...

That's easy enough to do...just write down the mileage every time you put gas in and then add it up at the end of the week/month...