Chevrolet Repair: chevy K1500 chugging and no power, cat converter, distributor cap

Question
Help truck was driving fine and the suddenly started to chug and had no power. drove home top speed 40mph, barely made it up the hills. Changed plugs,wires,distributor cap and rotor. Started it up it drove fine for about 2 miles and then started chugging again, it got worse the more I drove. Any ideas? Can't afford to take it in and have it diagnosed.

Answer
Hi Kym... you don't say what year and engine size so this is just a guess...check and see if the cat converter is plugged. check EGR and see if its working. check for bad ign module. check for plugged fuel system. i know its not much but hard to say what it is without the right info...hope this helps