help with fuel milage

[anthony96]

i recently tuned up my 96 XLT. replaced plugs, plug wires, air filter and fuel filter i also replaced the pvc valve.
at the same time i had to put in a new thermostat, one that was in was stuck open truck ran cold. i figure that was the problem. but after tuning and the thermostat change i only get 12 MPG with a lite foot!!! thats horrible, but before the work was done i was getting like 9 mph. any ideas on how to improve the milage and or did i miss something in the tune up?
please help
thanks
anthony

 

[aldive]

Did you replace the thermostat with a lower temp version than stock? If so, that could "confuse" the computer and give poor mileage.

What is your "normal" mileage?

 

[anthony96]

replaced the thermostat with the stock 195 unit.
the one that was in there had no stamp on it so i was assuming it was a stuck stat stuck open.
i have no clue what the normal milage is. i am the second owner of the truck. i got it with 37000 miles on it. now has 41000. i only recently noticed the poor milage. i get 225 per tank full or around 225 per 18 gallons. before it was more like 160 per tank.
Anthony

 

[B94Sport]

It's a little early mileage-wise for them to go, but you could check the O2 sensors, Throttle Position Sensor, and Fuel Pressure Regulator. The FPR on mine went out, which killed the mileage and fouled up the O2 sensors. I replaced them all at the same time and can now get close to 20 mpg on the highway. But my truck has 111,000 on it. You might also want to check the MAS, it could need cleaned.

 

[aldive]

O2 sensors can go at any mileage. I had to replace one at 41k.

Good luck

 

[Kontrol-Trak]

Originally posted by anthony96
i recently tuned up my 96 XLT. replaced plugs, plug wires, air filter and fuel filter i also replaced the pvc valve.
at the same time i had to put in a new thermostat, one that was in was stuck open truck ran cold. i figure that was the problem. but after tuning and the thermostat change i only get 12 MPG with a lite foot!!! thats horrible, but before the work was done i was getting like 9 mph. any ideas on how to improve the milage and or did i miss something in the tune up?
please help
thanks
anthony

I have a 95 EB and get about 13mpg with mixed city & highway driving. I got a K&N drop-in, new plugs & wires, PCV valve and thermostat but they didn't help mileage at all. Oh well...at least gas is cheap now

 

[sideswipe]

I get about 12/17 (city/highway) in my 98 with no performance mods.

 

[aldive]

I get 20/23 city/hwy in my SOHC 99.

 

[ok89]

i get 14/19 in my 98 XLT
i took it in to have a tune up done so i will report back to see if i get any improvements

 

[Alec]

If it's never been done, you might want to get the fuel injectors cleaned. Usually the fuel additives are enough, but if they're really messed up get them done by a mechanic. Also, 40k is about time for new tranny fluid. Old tranny fluid can put more drag on the driveline, robbing power/mileage. 12 mpg sucks for a 96!