you look for a wet spot, let your nose guide you to the gas smell. no you cant use putty to fix it, its a hi pressure line. you need to cut it off where its leaking and install a dorman repair kitt, has a new quick connect to click on the fuel rail.....those QC's also fail and leak gas. o rings inside fail.

stalling could be anything, from lack of fuel pressure to a large vac leak. dont sound like a crank sensor they stall driving at speed. tack quits working in many cases.