Was driving the mustang to work this morning, car was running perfect, stopped to get gas, a few miles later, noticed the engine started stumbling real bad at idle, and would surge when driving, I pulled over to see if I could see anything obvious, nothing, I had to turn the idle way up to get out of there because I kept stalling everytime I would slide it into drive. I got it home, barely, and started pulling the plug wires, #'s 2,3,5, and 8 did not have any effect on the RPM or engine running. I pulled the #2 spark plug out, looked OK, . I have been running the pertronix ignition, flamethower wires, and coil for about a year now, spark plugs are bout' the same age. I am thinking at this point my pertronix unit is shot not firing the 4 plugs, but I wanted to see if I missed anything, or maybe I am way off, what do you guys think?? any another input or help would be appreciated.