Does your car Idle funny?
First, I think you should check your TPS.
If you have a code reader(or know someone who does) check for codes too.
I'm not real familiar with the 4.6, maybe make sure any vacuum lines are in good shape.
If you were running lean, the more fuel you required the worse it would get (ie. At higher RPM it would get worse). So I don't think you're running lean.
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1995 Mustang GT