Floor it to start

My 93 g20 350 TBI van ran great when parked.(ran low on gas) Went
to start two weeks later and will not start without flooring the pedal. I
took it to the gas station and put half a tank of gas in it. Even after
it starts it idles rough and unless I floor it to give it gas it will die. It
looks like enough gas is getting into the tbi and when it's roughly idling
the exhaust smells like gas. I changed the cap and rotor and it's getting
spark. I even put an msd box I had on it and still no change. Please help
I'm going on vacation in a couple of weeks and the family's counting on
me to get the family truckster going again. Thanks