my oil pressure drops when I slow down or stop

It's common for the oil pressure to drop as engine rpm does!...As long as it has some oil pressure, should be ok.

To be sure u have oil pressure u can purchase a oil pressure tester from harbor freight under $30 if that says when ur gauge is 0 you have proper pressure try replacing the oil pressure sending unit with a mopar (oem) oil pressure sending unit. If the gauge still acts up put a small amount of dialect grease in the plug under the gauge cluster being cautious to wipe excess completely.