Yama

I have a stock 2000 Mustang GT and I average about 9-10 mpg. Does anyone know what could be wrong? Im going to college and gas is killing me.

bopiela

How do you typically drive? A lot of rush hour traffic, idling, minimal moving? Mostly expressway? Any check engine lights? How many miles on your car? Maintenance done regularly?

Yama

I honestly just drive regular with the speed limit i dont floor it or gas it unnecessarily. And no rush hour traffic, there arent any check engine lights, oil and oil filter change every 3 thousand miles, air filter is clean, spark plugs are good, brakes are good i mean i dont know whats causing it to eat so much gas.

Hangwire

Have your catalytic converters checked, they may be clogged. Thats about 50% gas mileage. I get 22-24 on a good highway tank.

Yama

no i havent got them checked, ill check them out. thanksss alot

kugzgt

check for a hole in your gas tank lol that sounds terrible!

teej281

Change the fuel filter. When I changed mine, I picked up 3 mpg roughly and mine wasnt even clogged. I think that may end up being your problem, and possibly your cats. Check the fuel filter first. Does it feel sluggish at all?

uberstang1

Cats/air filter/fuel filter/plugs.

cliffyk

How many miles on it? As O2 sensors age their output drops, the lower voltage makes the PCM think the engine is running lean and it compensates by making the mix richer--this can and does happen with no DTCs being thrown.

On cars that see a lot of highway cruising O2 sensors can last 100k+ miles (mine are headed for 105k and are working fine), however on cars that are used mostly around town and routine short trips (only 3 to 5 miles) they can be shot in 50k miles.

LS WHAT

have you ever given it a complete tune up?

do you have a locking gas cap?