Hey guys,

I really need some help. So I bought a 2004 Mustang 3.8L V6 Convertible about 10 months ago, it has about 89k miles. The problem is that I am getting terrible mpg. In the city I would get about 12 and on the highway I get around 17. After I bought the car, I changed the oil, transmission fluid, spark plugs, air filter, fuel filter had injectors cleaned by mechanic, brakes changed. I also used 2 Chevron Techron bottles, seafoamed the engine, still no luck. I am not right foot heavy or anything, I drive normally. I also had my friend scan the car for codes, there is absolutely no codes whatsoever, shows everything working normally. So I am running out of options, I can't keep spending money on things that are probably not helping the situation. Do you guys have any suggestions that might've been overlooked?

Thanks!

 

You should get much better mileage than that.

When you get on it do you see any black smoke coming out of tailpipe?

 

I know right! I checked, there is no black smoke coming out of the exhaust. I also placed papers underneath the car couple of days ago to check for leaks, there was none... :/

 

Pull a spark plug, look at the electrode tip, should be a light tan to maybe a couple shades lighter using ethanol fuel. That will verify if it is getting to much gas.

If that checks good, then I'd look at rolling resistance on the car. What could be dragging it down. Brakes, tire pressure, bearings, etc.

And you looking for leaks is a great idea. Is there any smell of gas at all when the car is idling in park. This s when the fuel system will leak as that's when it's under pressure from the fuel pump running.

Post back with any updates. Good luck