Wayne,
Do you have Electric fans controlled by a Thermostatic switch? I had a fan motor go bad, when it was turned on by t-stat it was drawing so much amprage the ignition voltage droped to low and would misfire. I thougth it was in the ignition

I have a complete Mallory setup . I converted from an older HyFire IVto a new HyFire VI. My car would idle and run just fine untill I'd get several miles away. Then it would start to fart and belch. It would idle just fine but trying to get the car away from a stop or even carry the car down the road. I bypassed the Box and ran on the coil and distributor using the supplied shortingor bypass plug. Made all the difference. I returned the box before the warranty expired and orded another Mallory HyFire VI and everything is great now. Stuff happens.

Wayne.... I read thru the entire string and it looks like you may have landed on something. I have my MSD box installed under the dash and it does get surprisingly hot for its location. I can't imagine how much hotter the MSD box can get when mounted in the engine compartment! Mine is very warm to the touch on a mild summer day.

While the Cobra is tucked away in the garage for at least 2 more months (really cold and windy here today, wind chill is something like -35) I believe that I did find the problem as I indicated above. I had a 10 wire connector that wasn't properly hooked together. I took it apart, cleaned all the connections while I was at it, put it back together, and taped the two plastic connection blocks together. I didn't have any difficulties after that.

Iniitally I had my MSD box under the hood but I decided to move it into the trunk when one of my buddies that races quite a bit mentioned that MSD boxes get hot on their own and do not like to be over heated. I store my car in the winter months so I am always looking for projects to keep me busy. I moved the box into the trunk and make a wiring extension using the proper colour wires. I soldered all of the connections and covered each in shrink wrap to make sure that I did not have a problem in the wiring. An added benefit is that it keeps the engine compartment more tidy.

By the way, the wiring connector that gave me the problem had nothing to do with placing the box in the trunk. It was a connector used to separate the wiring harness under the dash from the rest of the wiring harness especially that part under the hood. ;)

Wayne