Bad Gas Mileage

[06V6Andrew]

Just wondering, does anyone else out there have a 4.0L mustang that all of a sudden got bad gas mileage. Was getting 400 to a tank now only about 300-320. Tires good just did a tune up, cleaned air filter, new oil change, new tires, new filter....but still no change in mileage...It seems to have more power than before and sounds a little more aggresive(i have been told the pitch and "rumble" as change quite a bit.) but still i would rather have the gas mileage than anything else right now. Driving 50 miles to work and back eats up the fuel.

Thanks for any input in advance.

[blown96cobra]

winter gas sucks!

[black90lx]

yea the gas mileage in my truck went down too.

[Kevin1989]

my trucks mileage goes down aloott in the winter

[djom1cincy]

Keep your foot out of the pedal. On a serious not I haven't notice but I don't pay for my gas so I don't pay that much attention.

[06V6Andrew]

I wish it was winter but this started during the spring time. Maybe it's just wear and tear on the engine...it just rolled 90000 miles on it.

[1987coupe]

i think that every time it sees my coupe it just gets jealous lol

[marauder]

Try putting a can of that Restore in it on your next oil change, that worked well on my mom's old 200k+ mile chevy lumina. We used it every oil change since it was bought. We weren't sure the exact mileage but we only changed the alternator and battery on it the entire time we owned it, I think she bought it with 30-40k miles on it. Anyway, the stuff works and does help improve mpg.

You checked your air filter lately? Try running some lucas injector cleaner through a tank too.

[Mista Bone]

winter gas sucks!

It is NOT the gas.

The real cause is the engine takes forever with colder temps to get out of cold start loop, even longer if you use the heat.

What would take 5 miles to get to say 170 degrees water temp might now take 20-25 miles. So that extra 15 miles is like driving with the "choke" on.

Also with the colder air temps the IAT over compensates by adding more than needed fuel.

[black90lx]

thats why i have thought about getting a block heater but not sure if they really work and are worth the money.

[06V6Andrew]

Tony knowing your coupe doesn't move i think my car thinks it don't run! LOL! Yeah i have done everything to this car to get the mileage back up but nothing helps. I think i am going to the the fuel injector cleaning as my last attempt...when i get a chance.

[redfirepearlgt]

Never saw any mention of cleaning the TB or the MAF. This should be done as well. 90K on the Fuel injectors would likely require more than a simple can of fuel injector cleaner for any improvement IMO if there is any loss of atomization due to clogging assuming they have never been cleaned before. Someone on the site was offering injector cleaning service in the services section. you could talk to them. Mista Bone makes a good point with regard to the winter time warmup as well. This has been a much colder winter than usual already.