Gas only leaks when car is running what could it be

Common sense answer is NO. However, my '94 Sl500 with a book value of around $1000, I have driven it for two years this way. Asked a repair shop if They would give me $500...,no.. My leak is at the fuel pump in the tank Two drops every 6 seconds,only when running, away from the catalytic converter, and exhaust pipe. Stupid..stupid..stupid. My only car, retired, it will catch on fire sooner or later. You and the ML 430 are worth the codt of repair.