Hey guys, figured I'd join here to get some ideas. First post. I'm in BC Canada, and am posting in regards to my girlfriends 2000 Mustang 3.8 auto. She's had it for a few years now, and since she's had it, it's been a pig on fuel. Yes I know v6's aren't known for their economy but to me this thing isn't as good as it should be. I've had a 1990 5.0 lx in the past and it was better.

The car has a bbk cold air intake, dual flowmaster cat-back, and DID have a diablo tune, which today I took out and put the car back to factory tune. I don't really believe in the little handheld tuners aways. Also all tire pressures are what they should be at.

Just recently did a tune up, (plugs, wires, cleaned air filter, replaced fuel filter). Car has 221xxx kms on it. In the recent past it's had evap codes, for small evap leak. Never ended up finding the problem, but the code went away. However it does take forever to fill it, keeps clicking off. Fuel tank's not venting and I'm wondering if that has something to do with the evap code it had. Plugged charcoal canister?

She drives it conservatively, and so do I as I know its not a powerhouse. Personally I'm against the idea of a 6 cylinder mustang, but the car was free and it looks good so why not. Doesn't smell rich when driving, nor does it smoke. Was thinking about testing the primary o2s to see if they're on their way out.

Just to this tank so far, it's gone through 1/4 tank and only gone 60 kms. She's lucky if she sees 300 kms to a 60 L tank.


Any ideas? Not a Ford guy, but I know the basics apply to all vehicles when it comes to this stuff.

Thanks.

 

Could be a lot of things at that age. First thing I'd check is to make sure there is no rolling friction (jack it up and spin the wheels). Check for brake calipers dragging, wheel bearings not spinning freely etc...

I'd chase down the EVAP code as well. If it threw a code, something isn't right.