I have a 5.0 automatic with a few issues i can start the car sometimes and it runs perfect other times i start it and then when i drive it it will bog down like it is not firing on all cylinders but why does this only happen occasionally

 

What does the exhaust sound like? Any sudden "woofs" of air pressure sounding like a light backfire at idle? Stumble or hesitation on acceleration? Could be a bad injector on it's way out. Check the cylinder temps with an infrared thermometer at each exhaust port on the exhaust manifold. The cylinder that is running significantly colder than the other three will be your culprit.

 

how old are plug wires, dist cap, rotor, plugs? are ground wires to motor tight and clean?

 

That sounds like a classic fuel starvation/low fuel pressure from a nearly-clogged fuel filter. When was the last time you changed it? Good luck.

 

Since you're only firing on half the cylinders you come to the 944 board huh

 

Could be a clogged cat. Could also be a bad track in the AFM. Could be reference sensor. Does it do the same thing if you rev the engine unloaded, or is it only if you are in-gear and moving? If it does it the same way unloaded, then it is likely AFM or reference sensor. If it only does it loaded, it is probably fuel starvation or exhaust back-pressure.