My brother's truck was doing the same thing and a new set of intake gaskets fixed it. I am pretty sure that it is common for the '99-'04 factory gaskets to leak.

 

Intake gaskets was it.
Thanks for the help guys.

 

Well I did the intake gaskets as I stated up above and it fixed my problem.
Right now in town I am getting 13mpg. Pretty good I think.
Tonight I changed plugs and wires(MSD WIRES)
Wow what a difference just in the acceleration so much smoother and less effort.
Fuel mileage should get a little better.

 

Glad to hear you got it fixed.