My 1989 van runs like crap

My van is a 1989 van 4.7 liter engine 86,000 miles on it. when i put it into gear the car dies. when i eventually get er goin it doesn’t have any power goes like 20 mph for a few miles no matter how much i romp on the gas. when i get it up to speed it runs pretty good. but dies at stop lights i can smell gas pretty much all the time.

Ive tried replacing the fuel filter and the maps sensor and it ran okay for a day but then started running worse