It might be real handy to mention the model year of your Mustang. Why? The EVAP system is very different between a 96-98 and a 1999+.
Regardless of which Mustang you have for an older Mustang one of the 2nd places to look (after the gas cap), is the gas tank filler neck. There are two problem areas. The filler neck grommet and the filler neck itself rusting through. Especially if your filler neck has the plastic rock shield.
Finally, on some older model year Mustangs, an EVAP related DTC will not clear on it's own. The DTC code will have to be reset with an ODB2 reader or battery disconnect.
On newer Model year Mustangs, the DTC code will reset after a few successful drive cycles.
Soooo if you didn't reset the code, it's actually possible that the problem has been resolved but you just don't know it.
Regardless of which Mustang you have for an older Mustang one of the 2nd places to look (after the gas cap), is the gas tank filler neck. There are two problem areas. The filler neck grommet and the filler neck itself rusting through. Especially if your filler neck has the plastic rock shield.
Finally, on some older model year Mustangs, an EVAP related DTC will not clear on it's own. The DTC code will have to be reset with an ODB2 reader or battery disconnect.
On newer Model year Mustangs, the DTC code will reset after a few successful drive cycles.
Soooo if you didn't reset the code, it's actually possible that the problem has been resolved but you just don't know it.
