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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-

10.5 MPG?

  • Thread starter Thread starter impulse001
  • Start date Start date Jan 24, 2010
I

impulse001

New Member
Jan 16, 2008
84
0
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New Jersey
Jan 24, 2010
#1
  • Jan 24, 2010
  • #1
My mustang is killing gas. I took it out for a few days, filling it up with 93 gas before I left. I drove a total of 116 miles (as per the odometer) and filled up with 10.88 gallons of gas. that's 10.66 miles per gallon!

I have a stock 87 5.0 with only a Magnaflow exhaust. I just replaced the fuel filter maybe 4 months ago and rarely drive the car. I was going to replace my o2 sensors tomorrow because they are bad, could this cause such poor gas mileage?

Granted I did have some "spirited driving" but a lot of it was 5th gear highway driving going 70-80..
 

1987LXragtop

Member
Jan 26, 2008
837
3
18
Just outside Philly PA
Jan 24, 2010
#2
  • Jan 24, 2010
  • #2
im getting 10, also running rich and get on it a little bit
 

Tanus

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Dec 11, 2009
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A to the Z
Jan 24, 2010
#3
  • Jan 24, 2010
  • #3
thats pretty bad, I just figured mine a few days ago, I get just over 15mpg, in the city, ripping it like the whole time,haha.

my car runs low 12s too, has 325RWHP

edit- nice avatar!! makes me wanna spin in the middle on a swivel chair with my pants down, make the same sound as the baseball card I use to put against the spokes of my bicycle, haha
 

tannerc91gt

This last 25% is foreign territory at this point
Founding Member
Nov 29, 1999
4,392
2,967
234
Indiana
Jan 24, 2010
#4
  • Jan 24, 2010
  • #4
I get 140-150 to the tank. But I also drive the hell out of it and it runs fairly rich.
I put about 1500 miles on it a year though so it doesn't bother me
 

mob

the guy who hits on his mom
20+ Year Stangneter
Oct 3, 2003
2,566
136
104
Dallas, TX
Jan 24, 2010
#5
  • Jan 24, 2010
  • #5
Somethings not right. I was getting 17mpg with a bcam and exhaust.
 
I

impulse001

New Member
Jan 16, 2008
84
0
0
New Jersey
Jan 24, 2010
#6
  • Jan 24, 2010
  • #6
Tanus said:
thats pretty bad, I just figured mine a few days ago, I get just over 15mpg, in the city, ripping it like the whole time,haha.

my car runs low 12s too, has 325RWHP

edit- nice avatar!! makes me wanna spin in the middle on a swivel chair with my pants down, make the same sound as the baseball card I use to put against the spokes of my bicycle, haha
Click to expand...

Haha, I don't know how you thought of that.. But it was funny.
 

25thmustang

Mustang Master
Sep 5, 2003
2,021
85
99
Montgomery, NY
Jan 24, 2010
#7
  • Jan 24, 2010
  • #7
Mine gets mid 20 mpg on the highway. Probably high teens around town.

My F250 gets 10-11...
 
I

impulse001

New Member
Jan 16, 2008
84
0
0
New Jersey
Jan 24, 2010
#8
  • Jan 24, 2010
  • #8
mob said:
Somethings not right. I was getting 17mpg with a bcam and exhaust.
Click to expand...

Could the o2 sensors be the problem? Or is there something else I should look at?
 

cenok is family

15 Year Member
Jun 25, 2003
1,409
69
79
Norman, Ok
Jan 24, 2010
#9
  • Jan 24, 2010
  • #9
anything that contributes to fuel mapping. maf, o2s, ect, act. check for vac leaks too. how does it run?
 
I

impulse001

New Member
Jan 16, 2008
84
0
0
New Jersey
Jan 24, 2010
#10
  • Jan 24, 2010
  • #10
cenok is family said:
anything that contributes to fuel mapping. maf, o2s, ect, act. check for vac leaks too. how does it run?
Click to expand...

Its running good now, I was having idle problems before but fixed some vacuum leaks and replaced the IAC and it runs good.

Also, I have an 87 5.0 so mine doesn't have a MAF, right?

Could you tell me where the rest are located and I will replace them? Thank you.
 

Tanus

New Member
Dec 11, 2009
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A to the Z
Jan 24, 2010
#11
  • Jan 24, 2010
  • #11
the air temp sensor went out on my buddies car and it ran super rich. best bet is to check for codes
 

MAC'n89Blckstng

Active Member
Jun 11, 2003
1,012
4
36
NJ
Jan 25, 2010
#12
  • Jan 25, 2010
  • #12
I noticed that with the winter fuel, my LX was getting worse and worse. Got down to 11.5 mpg and now I'm getting back up. I got 14.3 this last tank. And I'm not beating it up either. Winter fuel sucks. My buddies mazda 6 lost 30-40 miles to a tank and same for my buddies F150. I've seen the best mileage come from Sunoco 91 octane.
 

25thmustang

Mustang Master
Sep 5, 2003
2,021
85
99
Montgomery, NY
Jan 25, 2010
#13
  • Jan 25, 2010
  • #13
My truck went from 11 on average to about 9.5-10, and just last month saw two tanks at 8.5. Granted the hubs were locked in for some of those miles, due to our driveway being nasty, but yes the winter fuel does cause mpg loss.
 

Mr. Rustypwnz

Advanced Member
Jun 1, 2005
1,761
63
69
indianapolis/ valdosta ga
Jan 25, 2010
#14
  • Jan 25, 2010
  • #14
damn my car is getting around 23mpg lol i must drive a hybrid..
 

fiveohwblow

Official Member
15 Year Member
Jul 21, 2005
2,169
145
155
Jan 25, 2010
#15
  • Jan 25, 2010
  • #15
I got 27 in TWO bone stock 5.0's.... problem is they didnt stay that way

I would definitely say something is wrong. Dont know what, but start with what you know is wrong and work your way up...
 

MAC'n89Blckstng

Active Member
Jun 11, 2003
1,012
4
36
NJ
Jan 26, 2010
#16
  • Jan 26, 2010
  • #16
My LX has a brand new tune up with everything replaced. The fuel up here in the cold states gets additives that reduce the MPG.
 

ID89GT

10 Year Member
May 26, 2008
1,659
18
49
Spokane Valley, WA
Jan 26, 2010
#17
  • Jan 26, 2010
  • #17
I would def be replacing the 02 sensors asap, that could be your problem.
 
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