Your 2003 mustang 3.8 just started using a lot more fuel no leaks it has 66000 miles?

Make sure the basics like tuneup has been done. If not its time anyway to put in some new filters & ignition parts (good quality parts!!). Do an proper fuel injector service also. If a check engine light is on take care of it also. You may also want to get a diagnostic done and then do the work yourself to save some guessing. The above suggestions are just from a maintenance point as the vehicle is at that mileage and no symptoms were given.

First answer by Bug217. Last edit by Bug217. Contributor trust: 158 [recommend contributor]. Question popularity: 1 [recommend question]