12 mpg???

DJack · August 31st, 2011, 01:50 AM

Been trying to work this problem out for awhile but figured I should gets some opinions before I continue.

For the past few months I've been getting about 12mpg in the city and 18 on the highway.

No cels, new cai about a year ago, oil changed every 3000, just changed spark plugs last week (this got me to 14 mpg on my last fill up).

My next step is going to be O2s but I figured there would have been a code thrown or something. Maybe their just dirty? In that case can I just clean them with something or should I replace all of them?

Maybe I'm missing something?

6ER THEN I 8ER! · August 31st, 2011, 02:02 AM

whens the last time you replaced your fuel filter? do you clean your air filter at each oil change as well...the starting of a clogged cat can also cause this (usually that will throw a code though)....

start with the fuel filter and see where that gets you

DJack · August 31st, 2011, 02:06 AM

Sorry forgot about that, fuel filter is no more than a year old either

6ER THEN I 8ER! · August 31st, 2011, 02:23 AM

Originally Posted by DJack

Sorry forgot about that, fuel filter is no more than a year old either

where are you getting your gas from

DJack · August 31st, 2011, 02:32 AM

The place I work at (kwik trip). They carry top tier gas for anyone that checks that stuff. Typically I'm running 89 octane, with 91 (premium ethanol free) I get a few extra mpg but thats pretty normal.

6ER THEN I 8ER! · August 31st, 2011, 02:47 AM

i'd just go back through your list of things that effect MPG and check them off 1 by 1 till something changes..about all you can really do...

DJack · August 31st, 2011, 02:48 AM

So should I bother with the 02s ?

Tang Stang · August 31st, 2011, 09:30 AM

How many miles are on the O2's? How long has it been since you cleaned your MAF?

DJack · August 31st, 2011, 12:58 PM

I've had the car for a little over a year and put probably 15000 miles on it since then. Before that I'm not really sure what the upkeep record was, I haven't touched the 02s since I've had it and haven't given the maf a cleaning either.

ReverendDexter · August 31st, 2011, 01:18 PM

Wouldn't be a bad idea to get the O2s... fwiw, I've been hearing some bad things about Bosch lately, so I'd go with Densos.

Also, how old are the plug wires? What about the coil(s)?

Green_6er · August 31st, 2011, 05:47 PM

does the car have any significantly less power? might be coil pack. although that would throw a code.... carry on.

DJack · August 31st, 2011, 08:23 PM

Wires didn't look bad when i changed the plugs. As for the coils, they've been on since i got the car so not too sure.

Looks like I'll check out the o2s first, should i give a shot at cleaning them or just go ahead and replace them?

If its possible to clean them I assume I'd just take a wire brush to it or something?

If I replace them should I give a shot at replacing one at a time to attempt to find one bad one and save a bit of money or replace them all at the same time?

Green_6er · August 31st, 2011, 08:54 PM

just replace both of them at the same time. do it right the first time.

1slowv6 · August 31st, 2011, 10:24 PM

you cant clean O2 sensors.... that will ruin them so DONT do that and your car would set a code for 02 sensors

i would get ur codes read because your SES light could be out.

how does it idle? does it seem like its misfiring at all...

fuel filter takes like 5 minutes to do and costs $8 so start with that just cause but dont go immediatly after your 02 sensor because its probably fine.

but yeah get ur codes read at like an autozone its very strange ur not throwing a code with that kinda mileage... are you sure ur calculating it correctly too?

DJack · August 31st, 2011, 11:02 PM

My last trip totaled 174 miles on a full tank, can remember the exact amount of gas i ended up putting back in it but it came out to about 14 mpg.

I did the filter myself less than a year ago, i can't imagine it needs to be done again but I guess it wouldn't hurt.

Is there anyway to purposely set the ses light off to see if its working instead of taking it somewhere?

Tang Stang · September 1st, 2011, 08:47 AM

Originally Posted by DJack

Is there anyway to purposely set the ses light off to see if its working instead of taking it somewhere?

It should illuminate when you turn the key to "ON" before starting the car.

Originally Posted by DJack

If I replace them should I give a shot at replacing one at a time to attempt to find one bad one and save a bit of money or replace them all at the same time?

You'll only change the front two, not all four. Before you do that, I'd suggest cleaning the MAF (free). Also, check that your tires are inflated properly, you don't have a brake caliper hanging, etc.

DJack · September 1st, 2011, 01:17 PM

Just took a look at the lights to make sure they light up as I turn the car on and can see the ses light but don't see a cel light... Is there a cel and ses or are they both essentially the same thing meaning I would only have a ses light?

Tang Stang · September 1st, 2011, 01:28 PM

Ses = cel

DJack · September 16th, 2011, 07:59 PM

Well I just finally got around to getting some work done on this, managed to change the O2's and clean the MAF. Wont know if it helped for about another week but fingers crossed!

Here's what the old O2's looked like:

The passenger side o2 was a pain in the ass!

DJack · September 16th, 2011, 08:04 PM

BTW my cars at 130k right now so I'm assuming these were stock given their appearance and the fact that they are oem.

August 31st, 2011, 01:50 AM	#1
DJack Regular 2000 Mustang V6 Join Date: Jun 2010 Location: Eau Claire, Wisconsin Posts: 66 iTrader: 0 reviews	12 mpg??? Been trying to work this problem out for awhile but figured I should gets some opinions before I continue. For the past few months I've been getting about 12mpg in the city and 18 on the highway. No cels, new cai about a year ago, oil changed every 3000, just changed spark plugs last week (this got me to 14 mpg on my last fill up). My next step is going to be O2s but I figured there would have been a code thrown or something. Maybe their just dirty? In that case can I just clean them with something or should I replace all of them? Maybe I'm missing something?

August 31st, 2011, 09:30 AM	#8
Tang Stang Hardcore Enthusiast 2004 Mustang GT Join Date: Sep 2010 Location: Imperial, MO Posts: 1,961 iTrader: 2 reviews	How many miles are on the O2's? How long has it been since you cleaned your MAF? __________________ Rod @ AzzKicker Cars 2004 Ford Mustang GT-The Driver-BBK CAI, PP TB & Inlet, Steeda UD's, SLP LM1, & 3.73's. 1990 Mercury Cougar XR7-The Meth Addict-5.0L DOHC Stroker w/2.1L KB SC. 1995 Ford F150-Mud Toy-5.0L, 4x4, 33's, & Warn 8274 Winch

August 31st, 2011, 01:18 PM	#10
ReverendDexter Priest of the Car Gods Clapped-out '90 GT 'vert ~5.5 seconds off TTOD :( Join Date: Jan 2007 Location: Rohnert Park, CA Posts: 13,808 iTrader: 0 reviews	Wouldn't be a bad idea to get the O2s... fwiw, I've been hearing some bad things about Bosch lately, so I'd go with Densos. Also, how old are the plug wires? What about the coil(s)? __________________ O o /¯/______________________ \|BLAAAAAAAAAAAAAAAAAAAAAAAAARGH!!! \_\

August 31st, 2011, 10:24 PM	#14
1slowv6 Enthusiast 2000 v6 mustang Join Date: Nov 2010 Location: St. petersburg FL Posts: 738 iTrader: 1 reviews	you cant clean O2 sensors.... that will ruin them so DONT do that and your car would set a code for 02 sensors i would get ur codes read because your SES light could be out. how does it idle? does it seem like its misfiring at all... fuel filter takes like 5 minutes to do and costs $8 so start with that just cause but dont go immediatly after your 02 sensor because its probably fine. but yeah get ur codes read at like an autozone its very strange ur not throwing a code with that kinda mileage... are you sure ur calculating it correctly too? __________________ If Nissan motorsports is Nismo..Wouldn't Honda motorsports be Homo?

September 1st, 2011, 01:28 PM	#18
Tang Stang Hardcore Enthusiast 2004 Mustang GT Join Date: Sep 2010 Location: Imperial, MO Posts: 1,961 iTrader: 2 reviews	Ses = cel __________________ Rod @ AzzKicker Cars 2004 Ford Mustang GT-The Driver-BBK CAI, PP TB & Inlet, Steeda UD's, SLP LM1, & 3.73's. 1990 Mercury Cougar XR7-The Meth Addict-5.0L DOHC Stroker w/2.1L KB SC. 1995 Ford F150-Mud Toy-5.0L, 4x4, 33's, & Warn 8274 Winch

August 31st, 2011, 02:02 AM	#2
6ER THEN I 8ER! Banned Join Date: Apr 2007 Location: Portland, TN Posts: 17,515 iTrader: 3 reviews	whens the last time you replaced your fuel filter? do you clean your air filter at each oil change as well...the starting of a clogged cat can also cause this (usually that will throw a code though).... start with the fuel filter and see where that gets you

August 31st, 2011, 02:06 AM	#3
DJack Regular 2000 Mustang V6 Join Date: Jun 2010 Location: Eau Claire, Wisconsin Posts: 66 iTrader: 0 reviews	Sorry forgot about that, fuel filter is no more than a year old either

August 31st, 2011, 02:32 AM	#5
DJack Regular 2000 Mustang V6 Join Date: Jun 2010 Location: Eau Claire, Wisconsin Posts: 66 iTrader: 0 reviews	The place I work at (kwik trip). They carry top tier gas for anyone that checks that stuff. Typically I'm running 89 octane, with 91 (premium ethanol free) I get a few extra mpg but thats pretty normal.

August 31st, 2011, 02:47 AM	#6
6ER THEN I 8ER! Banned Join Date: Apr 2007 Location: Portland, TN Posts: 17,515 iTrader: 3 reviews	i'd just go back through your list of things that effect MPG and check them off 1 by 1 till something changes..about all you can really do...

August 31st, 2011, 02:48 AM	#7
DJack Regular 2000 Mustang V6 Join Date: Jun 2010 Location: Eau Claire, Wisconsin Posts: 66 iTrader: 0 reviews	So should I bother with the 02s ?

August 31st, 2011, 12:58 PM	#9
DJack Regular 2000 Mustang V6 Join Date: Jun 2010 Location: Eau Claire, Wisconsin Posts: 66 iTrader: 0 reviews	I've had the car for a little over a year and put probably 15000 miles on it since then. Before that I'm not really sure what the upkeep record was, I haven't touched the 02s since I've had it and haven't given the maf a cleaning either.

August 31st, 2011, 08:23 PM	#12
DJack Regular 2000 Mustang V6 Join Date: Jun 2010 Location: Eau Claire, Wisconsin Posts: 66 iTrader: 0 reviews	Wires didn't look bad when i changed the plugs. As for the coils, they've been on since i got the car so not too sure. Looks like I'll check out the o2s first, should i give a shot at cleaning them or just go ahead and replace them? If its possible to clean them I assume I'd just take a wire brush to it or something? If I replace them should I give a shot at replacing one at a time to attempt to find one bad one and save a bit of money or replace them all at the same time?

August 31st, 2011, 11:02 PM	#15
DJack Regular 2000 Mustang V6 Join Date: Jun 2010 Location: Eau Claire, Wisconsin Posts: 66 iTrader: 0 reviews	My last trip totaled 174 miles on a full tank, can remember the exact amount of gas i ended up putting back in it but it came out to about 14 mpg. I did the filter myself less than a year ago, i can't imagine it needs to be done again but I guess it wouldn't hurt. Is there anyway to purposely set the ses light off to see if its working instead of taking it somewhere?

September 1st, 2011, 01:17 PM	#17
DJack Regular 2000 Mustang V6 Join Date: Jun 2010 Location: Eau Claire, Wisconsin Posts: 66 iTrader: 0 reviews	Just took a look at the lights to make sure they light up as I turn the car on and can see the ses light but don't see a cel light... Is there a cel and ses or are they both essentially the same thing meaning I would only have a ses light?

September 16th, 2011, 07:59 PM	#19
DJack Regular 2000 Mustang V6 Join Date: Jun 2010 Location: Eau Claire, Wisconsin Posts: 66 iTrader: 0 reviews	Well I just finally got around to getting some work done on this, managed to change the O2's and clean the MAF. Wont know if it helped for about another week but fingers crossed! Here's what the old O2's looked like: The passenger side o2 was a pain in the ass!

September 16th, 2011, 08:04 PM	#20
DJack Regular 2000 Mustang V6 Join Date: Jun 2010 Location: Eau Claire, Wisconsin Posts: 66 iTrader: 0 reviews	BTW my cars at 130k right now so I'm assuming these were stock given their appearance and the fact that they are oem.

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