Could be the thermostat housing cover gasket or upper hose where it connects to therm housing, bypass hose, coolant temp sensor or water pump. There is a weep hole on the bottom side of the WP that will leak when the WP bearing and seal are going bad. It could also be the timing cover gasket. But probably not, unless some work was done on it.

 

wow I have a 99 v6 stang and its a good car. I agree no replacement for a 5 speed GT. My gt has been sitting for about 3 years so I know how you feel about your truck. The 99 was bought as a dd when gas prices were up. Got it for 2000 so the few issues it has I can deal with for now.

My ram has been sitting for 7 months while I rebuild the engine. So again I feel your pain.

It just takes some time and patience. You'll get it.