View Full Version : only getting 10 MPG

04-20-2003, 05:57 PM
im only getting about 10 miles a gallon out of my 89 SC...what would some reasons be...i DONT have a heavy foot either...


Thomas A
04-20-2003, 11:52 PM
Well, lets see. It could be a number of things.

Leaking Fuel Injector
Leaking FPR
Driving w/park brake on :D


Tim Groth
04-20-2003, 11:59 PM
I would change/check the following:

Fuel Filter
O2 sensors
Fuel Pump

Also, I don't know if any others can attest to this, and please keep in mind this is the WORST case senerio is the Headgaskets about to let go. I know before mine went I was averagin around 12.3 mpg and I had no signs of problems at all! Until I was sitting at a stop light and I thought I was in the clouds.

Anyways good luck.


04-21-2003, 12:58 AM
you might try a real good tune up...plugs, wires, filter(s), the whole nine yards

04-21-2003, 01:04 AM
whats the most boost you see?

you could have a boost leak

also how many miles does she have on her?

04-21-2003, 01:10 AM
its an 89 and has 94000 miles on it...i just got a new fuel pump and plugs, as well as many other things fixed...

04-21-2003, 01:46 AM
Driving style maybe?

Maybe a fuel leak

04-21-2003, 03:36 AM
What were the "Many other things fixed" recently? Did the car get better gas mileage before "Fixing" it? Could be a stuck EGR or PVC but this would make the motor ping. Have you checked all vacuum hoses and their routing? Is it hard to start or does it lack power? Could be a clogged catalytic converter. Does it show any other unusual symptons, like overheating, stalling, backfiring, or morning sickness? My experience has been that when my car is not getting such good gas mileage, it is also not running too good. Does the check engine light come on? Have you checked to see if any codes are stored in the computer? Is the car an automatic or five speed?
As you can see it would help to have as much information as possible to narrow down the problem or at least help you look in the right direction.

Do you only drive uphill? Pulling a boat? Against a head wind? While dragging your feet?

04-21-2003, 09:50 AM
I think that you blew your supercaharger fuse. Replace that, and you should be good to go.


04-21-2003, 10:49 AM
~~~ supercharger fuse? and where do you plug it in? the the oil fill hole ?

the supercharger is controlled by vaccum as far as the bypass is conserned

04-21-2003, 10:59 AM
Joke..........duh. :D


04-21-2003, 11:22 AM
ford has done stranger things

04-21-2003, 12:04 PM
i think your flux capacitor might be leaking,

um, seriously though

plugs and wires would be my guess, and maybe lighten the weight in your right shoe :p

04-21-2003, 07:54 PM
I would definatley upgrade your supercharger fuse to the new titanium insert. Also give your muffler bearings a check.. they still used petrolithium back in the 80s. The teflon bearings are much better.

I would also check your oxygen sensors.. after the other serious things people said. :)

Oh yeah, and don't neglect your air filter. They can have a suprising impact on gas mileage.

04-21-2003, 08:23 PM
Another thread hijacked?

The first, and most painful thing to check for poor fuel economy is the Fuel Pressure Regulator. It's buried under the Intake Plenum on the drivers side of the motor near the firewall. Pull the vacuum line off it and check for any fuel in the line. If there is fuel in the line, your regulator has failed and should be replaced.

If that's not it, the next thing would be to monitor engine coolant. Make sure the thermostat isn't stuck open. Running in warm up mode for extended periods due to low coolant temperatures could impact milage. Though I wouldn't think as much as you report.

My bet would be on the fuel pressure regulator.

04-21-2003, 10:36 PM
if you find a set of muffler bearings let me know i'm pretty sure a old vw beetle replacement water pump is nearby :)

04-22-2003, 02:19 PM
IN MY OPINION (only had this car for 9 months) is that it could be a boost related sensor also (if applicable;my turbocoupe has these)AirChargeTemperature(ACT) or Barometric Pressure Sensor, or the others mentioned. I know I got EXACTLY 10 MPG when the FPR went out on my 2.3 turbo.

04-22-2003, 04:36 PM
ive been getting 10 mpg in my car for teh past year, i just thought that was plain old normal, still runs great, and eats mustangs, so im happy