10.5 MPG?

[impulse001]

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]

im getting 10, also running rich and get on it a little bit

 

[Tanus]

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]

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]

Somethings not right. I was getting 17mpg with a bcam and exhaust.

 

[impulse001]

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

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

 

[25thmustang]

Mine gets mid 20 mpg on the highway. Probably high teens around town.

My F250 gets 10-11...

 

[impulse001]

Somethings not right. I was getting 17mpg with a bcam and exhaust.

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

 

[cenok is family]

anything that contributes to fuel mapping. maf, o2s, ect, act. check for vac leaks too. how does it run?

 

[impulse001]

anything that contributes to fuel mapping. maf, o2s, ect, act. check for vac leaks too. how does it run?

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]

the air temp sensor went out on my buddies car and it ran super rich. best bet is to check for codes

 

[MAC'n89Blckstng]

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]

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]

damn my car is getting around 23mpg lol i must drive a hybrid..

 

[fiveohwblow]

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]

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]

I would def be replacing the 02 sensors asap, that could be your problem.