Transmission shift problems

This just started happening drove to store came out started the truck put it in drive slowly eased the gas and the truck was very slow to take off. So, I stopped and turn it off and turn it back on shift into drive and go home like normal. Then it does the same thing two days later when I get home to check all the wiring under the hood disconnect the fuse box look at all connectors for broken or exposed wires, see nothing of the sort put everything back together and have no problems for about 8 days, then it starts all over again with the slow take off when put in drive it comes and goes.