engine missing, loss of power

I have a 94 2 wheel drive with a 4.3 vortec engine and 5 speed. It starts fine and seems to idle fine, but when you push the accelerator down a little bit, it will start to miss and loose power. After it fianlly picks up some rpm's it will run fine. I have changed the fuel filter within a year and have run sea foam through it. It doesn't do this everyday.
Some days it will run fine, but for most it will miss. Recently the check engine light came on and then went off. Keeps coming on and off. Anybody have any ideas?

have the code diagnosed, it will help in finding the problem. could still be a bad filter, they collapse. Not to sound dumb, but see foam, maybe you could explain further. Are you getting a steady stream to your tbi? disco fuel lines and blow through them to make sure there is not clog. Have you changed you plugs, wire, rotor, or cap recently. Lots of small things to consider.

I would start with trying to get trouble codes out of it. Locate the diagnostic link under the drivers side dash there should be a black 12 pin connector. Insert a jumper wire from pin A to pin B, they will be on the top row the farthest two to the right. Count the flashes and it will give you the trouble codes. If you do not get any codes I would start with a basic tuneup, and look for vaccum leaks. Do you have to press the throttle down any further after it starts missing to get it to pick back up again? Did you just pour the Sea Foam in the gas tank, did you suck it in through a vacuum hose to clean carbon off the inside of the engine? Or both maybe. Is this a TBI system? I can't remmbe what a 94 came with.