05 Altima 2.5 runs great but. Turns over but sometimes will not start

05 Altima 2.5 runs great but. Turns over but sometimes will not start, if it tries
to start but doesn't the engine sounds like it's missing badly and dies. I tried
starting 15 times once and it tried hit a few times but died each time. Then it
started and ran like a champ. I get a misfire cyl 2 switched coils it missed
again a week later same cylinder. Then another rough starting experience
and it said intermediate miss. When it has one of these fits I smell gas.
Yesterday it was cool and raining shut the engine off at fish ladder 10mins
later tried to start it turned over no igniting, tired again hit on a few cylinders
died and done this four or five times. Finally started with big puff of white
smoke drove home 70 miles ran like a champ. Started no problem this
morning. And so it's been for 5 months been to the prepare shop three
times...they can't find an issue.