some kind of lag

Guys my car is a automatic,when i first start the car its good but when i go to take off after reverse, it lags. It like does a putt putt and goes. Its weird. Wut do you guys think it is. I think its the fuel filter but i dunno. It has 43k miles on it so its not the spark plugs or wires. But im gettin new ones anyways. So thx for the help

perhaps a tranny service is in order...