gas mileage

[matt1517]

Ha, I bet everyone is tired of seeing my posts lol. Anyway, I am wandering if im getting bad gas mileage. I travel about 1 mile to work and back, yeah im lazy. And at 1/2 a tank I have just about 100 miles. Now if you do the math 18(in town driving)x15.4(full tank size) its about 277mpg, supposed to. I have replaced the spark plugs (gapped properly) new spark plug wires, and a clean air filter. I just want to know if there is anything else i missed. I am going to let the gas light come on and see how many miles I am at. I had the oil changed as well in the past month. After reading other posts I am making sure the E-brake isn't gripping or that the OD light isn't on(it does work). I had new brake pads put on last month. and from what I can tell they aren't grasping.

Since I have owned the car I have not let the gas light come on so I don't know if the gauge is faulty. The CEL is on, but I accredited it to a bad o2 sensor. Does Autozone get the code for you free or? I don't make hard stops or fast take offs, as I need the car to last.

 

[Skymarshal]

To find the mileage you are getting, divide the amount of miles you have driven on the tank by the fuel you put in to top it off (200 divided by 14 or whatever).

It sounds like you're getting about 13 MPG right now, which is definitely abnormal. Short drives are going to hurt a lot since the engine never warms up, but it still shouldn't be that bad. My V6 gets around 26 MPG in mostly highway driving.

Your CEL might be a clue. If the O2 sensors are bad, the engine might be running in open loop "limp mode", which richens the mixture a lot to protect the engine. Get the code pulled, and if your sensors need replaced then replace them ($35 each from Rock Auto).

 

[Adverse2Change]

I get 22 City, which is about a 25 minute drive to work each day with quite a bit of stopping.

 

[troyjack]

My 2000 3.8 is at about 23-24 hwy, and I drive basically nothing but highway. This was right after replacing:
- plugs and wires
- fuel filter
- o2 sensor

CEL was on before and I also figured it was the o2. We reset it after changing the sensor and 2 days later it came back on. But I've realized lately that my gas filler grommet is broken and leaks pretty bad when the tank is full or close to full, giving it the illusion of bad gas mileage. Worth checking out.

 

[matt1517]

well i took it to auto zone and the code they pulled was for a bad spark plug which i already replaced, cleared it and it didnt come back. im sitting at 1/4 a tank at 148mi...ill check that grommet.

 

[matt1517]

My 2000 3.8 is at about 23-24 hwy, and I drive basically nothing but highway. This was right after replacing:
- plugs and wires
- fuel filter
- o2 sensor

CEL was on before and I also figured it was the o2. We reset it after changing the sensor and 2 days later it came back on. But I've realized lately that my gas filler grommet is broken and leaks pretty bad when the tank is full or close to full, giving it the illusion of bad gas mileage. Worth checking out.

Your conclusion makes the most sense. I went driving around on 1/4th tank and i got 25 mpg or so (did the math). When I fill up the gas tank it seems to go down much quicker. But right now its lasting longer. I went and looked at what you referred to on the car and i poured gas in, no leaks though, do I need to fill it up so I can see if it leaks? I used a gas can to fill it slightly and there was no leak (I waited a while, and drove it around). Its kinda gay though, having to fill it up to see if your leaking gas. There was a rubber seal that was slid all the way down to the grommet, it looked like it was supposed to attach to the bottom of the trunk. <--- If that's of any importance.


It looks like I will fill it up and see if it leaks, gas is only 1.50 after all.


http://forums.stangnet.com/748604-how-replace-fuel-filler-tube-gasket-pics.html




UPDT*

Came Home from the store, CEL came on...

 

[MustangLX-5.0]

matt1517..if your talking about a real loose fitting rubber seal with 4 bolt holes,that does go up where the filler tube meets the trunk area.It's just there to keep dirt and water out.

 

[matt1517]

to Mustang 5.0 yeah thats the seal. I did fill up the car drove it around no leaks from that seal. In any case I got the CEL Number and its a misfire "on bank 1" due to 4 things some sort of vacuum leak, dirty fuel injectors,engine mechanical problem, and 1 other that didn't sound right. the guy at my auto zone has a 01 mustang v6 auto with the same code, he says its fuel injectors. I bought the STP level 2 cleaner for fuel injection and im taking it to the shop to have a sort of gum out done to it..

THE CODE THEY PULLED IS P1131- CLAIMS TO BE ANYTHING FROM DIRTY MAF- DIRTY FUEL INJECTORS<-- this is what google reveals.

P1130, P1131, P1132 (HO2S11 lack of switching, Bank 1)??


I looked into sea foam it said it was for 2-4 cycle engines???? yet I saw Leanz post where they were going to use it.

It does have a bit of a rough idle and though the car starts fine its got a bit of a weak start. So after I get this gum out thing force through the car tomorrow ill see what happens. Some people say that the computer is fooled into puting this code out and
that it could be a dirty MAFS.

If anything I just want the CEL to go away.


---> :SNSign: <---

 

[MustangLX-5.0]

It sounds like you have a couple of problems going on.A dirty MAF can cause it to run very rich thus fouling up plugs and even O2 sensors.Bank 1 is the drivers side.Your O2 on that side could be bad,primarily the front O2 near the header pipe.Pull the O2 and check it to see if it's all blackened.

You can save yourself some dough $$ by cleaning the injectors yourself.Seafoam DOES work.I'm the one that suggested Leanz use it in his fuel filter.Just pull the filter,empty gas out and refill with Seafoam.

If your plugs are clean and its misfiring on one or two cylinders then it's most likely a fouled injector.But you need to correct the cause of this fouling otherwise they'll just dirty up again.A combo of bad O2's and dirty MAF will allmost guarentee fouled plugs and injectors.

I've fouled up my injectors plenty of times.And cleaned them right up again using heavy doses of Seafoam in the gas tank.That's with less than a gallon of gas left.This method may be inconvenient for you though.

 

[matt1517]

It sounds like you have a couple of problems going on.A dirty MAF can cause it to run very rich thus fouling up plugs and even O2 sensors.Bank 1 is the drivers side.Your O2 on that side could be bad,primarily the front O2 near the header pipe.Pull the O2 and check it to see if it's all blackened.

You can save yourself some dough $$ by cleaning the injectors yourself.Seafoam DOES work.I'm the one that suggested Leanz use it in his fuel filter.Just pull the filter,empty gas out and refill with Seafoam.

If your plugs are clean and its misfiring on one or two cylinders then it's most likely a fouled injector.But you need to correct the cause of this fouling otherwise they'll just dirty up again.A combo of bad O2's and dirty MAF will allmost guarentee fouled plugs and injectors.

I've fouled up my injectors plenty of times.And cleaned them right up again using heavy doses of Seafoam in the gas tank.That's with less than a gallon of gas left.This method may be inconvenient for you though.

Haha, thats rich my brother just did seafoam to my dads van and his ford explorer the same day i took it to the shop to have fuel injector cleaner FORCED through it. after they did this to my car the CEL was gone drove home went to work came back etc. and it came on a day later. I did have to move the air intake when i put in new spark plugs, but all i did was slightly move it to the side. The MAF just gets dirty on its own?

Im NO expert but i did some research on some other forums where you can buy stuff to clean the MAF, at like a radio shack.

"""What you need to do is go to the local Radio Shack and get a can of spray tuner cleaner, #64-4315. Disconnect the NEGATIVE battery cable and remove the MAF from the vehicle. Spray the inside of the MAF with the tuner cleaner. Be very careful when you spray the hot wire. It is very thin and if it breaks, you will have to replace the MAF. Clean it well and let it air dry for 15 or 20 minutes.

Don't use carburetor or brake cleaner. They leave a residue and you will be right back where you started. Use ONLY the tuner cleaner, which dries residue free. When it's dry put it back in the vehicle and reconnect the NEGATIVE battery cable. You will need to drive the vehicle several miles to let the PCM "relearn" your specific driving conditions. Once that is done the codes will not come back and you should notice all the symptoms are gone as well."""

source--> Ford Mass Air Flow Sensors




If your plugs are clean and its misfiring on one or two cylinders then it's most likely a fouled injector.But you need to correct the cause of this fouling otherwise they'll just dirty up again.A combo of bad O2's and dirty MAF will allmost guarentee fouled plugs and injectors.

I've fouled up my injectors plenty of times.And cleaned them right up again using heavy doses of Sea foam in the gas tank.

When its fouled you need to get a new one put in or just sea foam it?


It looks like I need to do the steps in the following order.

1. clean the MAF
2. check drivers side o2 sensor
3. re clean the injectors with sea foam


Appreciate the help MustangLX-5.0

 

[MustangLX-5.0]

Speakin of MAF cleaners.CRC has a MAF cleaner you can buy at most auto parts stores.I dont use it because it's too expensive (allmost $7).What most dont know tho,you can use QD Electronic Cleaner which is allmost $2 less than MAF cleaner.Has the same exact chemical mix (CRC tricky marketing ).

Never heard that one about the Radio shack tuner spray.It's probably a very similar quick drying spray like the CRC stuff since it's meant for electronic parts.

You need to get yourself an inexpensive code scanner so you don't have to keep running out somewhere for a scan.Find out what the light came on for.Probably the same thing.

Just check the O2.Avoid step 3 once steps one and two are done.You shouldn't have to re-run cleaners through the system.


Oh and get yourself a Haynes manual (Not Chiltons).That's a BIG help.

 

[matt1517]

I already have a a Haynes manual...havn't had time to read it i work alot. 6 days a week so i have one day to anything car related...

Thanks, and I will look into what you mentioned.

 

[matt1517]

when i get the MAF housing out do I need to unscrew the sensor plate from it. or just use the cleaner While its in there?

 

[klotzstang]

Ha, I bet everyone is tired of seeing my posts lol. Anyway, I am wandering if im getting bad gas mileage. I travel about 1 mile to work and back, yeah im lazy. And at 1/2 a tank I have just about 100 miles. Now if you do the math 18(in town driving)x15.4(full tank size) its about 277mpg, supposed to. I have replaced the spark plugs (gapped properly) new spark plug wires, and a clean air filter. I just want to know if there is anything else i missed. I am going to let the gas light come on and see how many miles I am at. I had the oil changed as well in the past month. After reading other posts I am making sure the E-brake isn't gripping or that the OD light isn't on(it does work). I had new brake pads put on last month. and from what I can tell they aren't grasping.

Since I have owned the car I have not let the gas light come on so I don't know if the gauge is faulty. The CEL is on, but I accredited it to a bad o2 sensor. Does Autozone get the code for you free or? I don't make hard stops or fast take offs, as I need the car to last.

If you fill up and can fit that much gas into your tank, there is something wrong with your gauge settings.
There is supposed to be a few gallons still in the tank when it reads empty, to keep the fuel pump from destroying itself. It needs fuel to keep cool.
I, and others I know, usually can get no more than 12, maybe 12.5 gallons into a tank on empty.
I don't know of a fuel light, but you may be getting better mileage than you think.

Figure your mileage this way. Fill you tank to the top, then drive it a few days. Refill it. Divide the gallons used into the miles driven. More accurate than going by the gauge.

If you OD OFF light does not come on when you push the button, the bulb may be burnt out.

 

[matt1517]

If you fill up and can fit that much gas into your tank, there is something wrong with your gauge settings.
There is supposed to be a few gallons still in the tank when it reads empty, to keep the fuel pump from destroying itself. It needs fuel to keep cool.
I, and others I know, usually can get no more than 12, maybe 12.5 gallons into a tank on empty.
I don't know of a fuel light, but you may be getting better mileage than you think.

Figure your mileage this way. Fill you tank to the top, then drive it a few days. Refill it. Divide the gallons used into the miles driven. More accurate than going by the gauge.

If you OD OFF light does not come on when you push the button, the bulb may be burnt out.

Well I've had this thing where (and i dont know about mustangs that much) when i drive the car the gage goes down a bit then I come home, go to the car and it reads that it is more full than the day before?? Its weird.

I Just cleaned the MAF sensor as to Mustangs advice. And I disconnected the NEG battery side for 20 minutes hopefully this will erase the CEL. Im going to drive it around and see what happens.

Thanks for the info klotz, I didn't know about the 12.5 gallon limit. Even so thats like 216 miles at the very worst gas mileage. That seems about right, like I said after returning from the beach I had about 221 miles on that tank.

The Od off Bulb works. "...the OD light isn't on(it does work)."



*** Cleaned the MAF sensor rather thoroughly. Unhooked Neg batt cable for 20 mins. Drove it for about an hr and CEL came back on. I guess all I have to look at now is the front o2 sensor?

 

[MustangLX-5.0]

I've had 2 different gauge clusters in my dash.The current one works a lot better,which is from a 95 GT (using 96 PCB).With this one the fuel gauge is a lot more accurate.It's not empty until the needle goes fully to the left side of the shaded orange "E" area.My other gauge didn't even touch it and ran dry.Now when I fill up,the needle doesn't surge a whole inch past the "F" way off the scale.When it's full or empty,it's right on the dot.And it holds 14.5 gal.

Yes,dont remind me of the damaging effects of running the tank extra low (sucking chit off the bottom of the tank).I only did it to verify the gauge reading.

As for the MAF.Remove the bolts holding the MAF tube to the plastic housing.Spray in the backside where the screen would normally be.Make sure you get it directly inside that small tube where you can see the 2 small meter wires.I will assume you allready did this though...right?

is it misfiring? or just a CEL?
Posted via Mobile Device

 

[matt1517]

Yes I did spray it down already. I spread the inner tunnel 15 times as per the directions on the can. I did unbolt it from the front plastic piece but it didn't get me anywhere because the screen was still attached.


"Spray in the backside where the screen would normally be" for mine its stuck on the metal housing for the MAF. I sprayed through it.

The CEL is back on but I don't have a scanner yet. MY guess is that its still coming back saying a misfire.

How would I know if it was a bad o2 sensor? They could just be dirty over a period of years. Do I clean them or get a new one? Being 40-50 bucks each, this is a huge deal $wise.

 

[klotzstang]

Go to Auto Zone or most any parts store to get your codes read free. That is the best way to isolate a bad O2 sensor.
The other way involves using a VOM to get the resistance and voltage values.
An O2 sensor is a small heater with a varing resistance, (caused by heat ) changes in the votage and resistance tell the computer the amont of Oxygen passing out the pipes.

 

[MustangLX-5.0]

I knew you allready sprayed it.I just wanted to see if you got down the "mini tunnel".That screen should be glued to the plastic,not the MAF.

Anyways,no you can't clean O2's.The sensor inside is made of a special alloy.Spraying any cleaner on it would cause it to mis-read.And you can't always tell by looking at one if it's bad.I know I said to look for sooted up sensor.But it's a start.

And if you do have a volt-ohm meter,use that to determine if the o2 is faulty.Haynes manual has instructions on that.

 

[matt1517]

Im sitting here reading my haynes manual, and the only P-codes (OBD2) that look anything like the one I got is P0131- Upstream heated 02 sensor circuit low voltage (bank1). I guess Ill just replace it and see if it goes away. Do I need to order one or can I just go somewhere and pick it up?


And there is one other thing, Autozone's probable causes was a misfire on bank 1 but the code for it in the book is p0301 Cycl. no. 1 misfire detected. The original code i got was "P1131."


No, im not paranoid about the car, its just we had a ford escort that ran well then it blew a gasket amongst MANY other things and I hope this "Found On Road Dead" will last longer