Joust

Hi,
I started my truck after work today and it is not running right. Iit stutters as it revs and has little power (compared to normal).
no engine codes. plug wires and plugs look good. only 280000kms on it. I redid the head gasket a couple years ago.
it starts fine and idles ok although rougher than normal
slowing down is really smooth but when I put the gas pedal down it seems rough and as I said little power.
I was just thinking it is fuel. I'll change the fuel filter but i doubt that this would cause such a sudden change in behavior.
i had to get my gas tank welded last fall. so maybe some junk got in there.
was also going to try removing and cleaning the injectors but the fuel filter is the first thing to try.
it seems like fuel delivery to me. I know the fuel pump is on and I can hear fuel transferring in the regulator at the rail. I put a switch on my fuel pump relay to turn it on last winter when i was having a problem with it starting in the cold. at the end of that it turned out to be a rotten fuel line at the tank that lost the fuel pressure.
please help. advice?