i have a 2004 mustang v6 3.8L can anyone tel me what i need to do to get my gas mileage back to where it was when i got the car a year ago my mileage went from 22 - 25 mpg to 15 - 18 mpg and it is pissin me off so plz anyone with anything plz help me out with info

 

What has changed other than the mileage?
Have you tried to pull any failure codes?
Do the exhaust pipes look black inside?

Bad O2 sensors can cause a drop in fuel economy and not set off a check engine light before they completely fail.
Clogged or restricted catalytic convertors can cause a drop in fuel economy.
A dirty MAF element can do the same thing.
Resticted air filter.
Fuel leaks.
Dirty fuel injectors.
Thermostat stuck open.

Go to Autozone or Advance,I think they still pull codes for free.Get a list of any pulled codes and repost.

 

Check your tire air pressure

Give it a tune up

 

My guess would be a combination of the following. Air filter/plugs/and dirty 02 sensors. Replace all of them and you will see a pretty good increase in gas mileage.

 

+1

 

+1 on the tire pressure - makes more of a difference than people think...
Probably right on the combination of the above.

I know that Autozone still pulls the codes for free.

My .02!