383 misfiring when warms up? AHHHHHH

Ok Gents, 71 dodge monaco 383 , 2 barrel, everything stock. Replaced the coil and plugs and wires last year along with cap and rotor. Just had the vavles cover gaskets changed and new thermostat installed. When i start the car up idles perfect, drive it for about 5 minutes drives prefect then all of a sudden when i step on the gas the car spits and sputters. im lost ive checked all the wires, made sure they are pushed on good. drove to my buddies house like this .. car sat for about an hour. started it up , ran great after 5- 10 mins started spitting and sputtering again. :sSig_noob:

Im trying my best , i love my car, I will admit i am over my head with an older car, but how else am I gonna learn. Ive fixed so much stuff on it that i cant talk to my wife about it anymore haha she cant stand hearing about everthing that keeps breaking ! lol
Author: dustin71