Realistic fuel economy - Ford Forums

Nutdriver4773 · 11-02-2009, 12:51

Hi all:

Have a 92 Tempo 2.3L 4cylinder automatic. I am getting a consistent 25mpg out of this car.
It starts and runs just fine I did full tune up cap wires rotor and plugs, new thermostat. This baby has 158,000 km on it.
I guess my question is. Is 25mpg highway all Im gonna get and if it is low what can I do about it?

Thanks
Keith

jglen490 · 11-05-2009, 09:06

Without knowing where you are driving your highway miles (i.e., Nebraska plains, Colorado mountains) or your typical running speed (i.e., 55mph, 75mph), it's difficult to say. Under most conditions, 25mpg highway is low; I would normally expect more like 30mpg.

Have you pulled codes (other than the key dance)? An O2 sensor could cause it to run rich. The cat could be plugged up. Some "errors" do not result in the check engine light coming on. But don't start throwing parts at it. I'd start with a code reading.

Nutdriver4773 · 11-05-2009, 09:19

Yes ran a code test all systems pass, I think the car has decent power so I think the cat is ok. I put new exhaust from the cat back with new muffler. I live in Canada and it doesn't seem to matter hwy on a long trip or back and forth to work I live 15 minutes outside my city I get 25mpg driving 60mph. I was wondering about an O2 sensor.

jglen490 · 11-05-2009, 14:23

O2 is possible. An O2 sensor is going to provide feedback to the ECU in the form of certain voltage levels. You should be able, with a digital VOM, to read that feedback once the engine is warmed up. I was kinda hoping that the OBD-1 code reader would find a code such as "42", which would indicate a rich condition. It's still possible that some condition is occurring and no code is being set and the CEL is not being lit up.

Elliott · 11-05-2009, 14:31

Could be EGR valve. Not sure if it would code if starting to plug up, but I do know if it plugs you will have a hard time starting the motor and keep it running. Fuel economy will also suffer if it is starting to plug. Of coarse as others have said it could be the O2 sensor.

chipset · 11-05-2009, 17:52

Do you get your gas at the same place every time or where ever you find a station ?
Do you use Shell or Esso ? What pressure do you use in your tires ? Do you know what
pressure is in your tires ? What tires do you have ? These all make a differance. To find
out what you actually get for mileage you need a bottle test. How much junk is in your trunk ?

Nutdriver4773 · 11-06-2009, 09:51

Thanks for all the replies! Like I said the car starts and runs very well so Ive ruled out vacuum leak or egr (no codes). I have used the same fuel for years with other vehicles and had good or expected mileage, my tires are new and pressures good etc etc. Good point Jglen I will backprobe my O2 and see if I can get a reading. I guess my main question was should I be getting better than 25 and it seems the answer is yes. I work as a heavy duty mechanic for the city so I will borrow the scan tool and run another test and see if there was ever a 42 (I dont think there was anything in history) Thanks again!

**rtg143** · 11-06-2009, 10:00

I read an article several years ago where they used a special fuel program to test the different mileage changes that occur with the different situations. The biggest change in mileage was with the spark plug gap. Increasing the gap .005" lowered the mileage more then even 10psi low air pressure in the tires. Other changes were also negligable. Funny thing about it, they were using a mid 80s Tempo. That's how long ago the test was done.