have a constant water leak that appears one day after the car is driven, no visible leak when car is stopped after use only after car sits for one day does water stain appear on ground and reservior is low

add more and see if it goes down it might be your a/c that is leaking it thaws when you turn your car off

Same issue on my 1997 Thunderbird 4.6L. It was the intake manifold. It was a known issue with that generation of 4.6s. There was a recall. The recall was limited to 7 years, so I missed it. Not sure if the same issue was identified on the SVT.