The other day I was driving home and the car just shut off on itself. I coasted in a parking spot and tried cranking it but it wouldnt fire. it just cranked and cranked. i let it sit for a few minutes and it fired up fine. I drove about 10 miles and it shut off again. I had to let it sit again. I took it to a garage today to see if they could check the coil with a meter but the guy said the car had been running for an hour and it was fine. I picked the car up and drove home and it happended again. This time I had my stock coil on me. I unplugged the the MSD coil and box and hooked up the stock coil and it fired right up. It is working fine now but I am afraid it will do it again on the way to work tomorrow. What things should I look for? does this sound like a bad coil

 

The MSD box sounds suspicious. How old is the MSD?

If you hadn't said that, I'd say check the ignition module. I had a similar problem, went through 5 or 6 different modules until I bought an Accel and it has worked perfectly since then.

If it doesn't run with the MSD and does with the stock coil........sounds like the MSD is getting hot and failing somehow.

 

the MSD box and coil is about 3 years old. I just installed new MSD billet dist so the module is new.