i bought an MSD coil, got it hooked up. i drove it for about 10 minutes and it started misfiring again. when i put the original one in, it worked fine. i exhanged the MSD coil for a new one, and it kept misfiring within minutes. now i have the original one back in. is this a case of bad coils, or is it an engine problem that makes it misfire.

 

what part number MSD coil are you using

 

i have no idea. both times i returned them because i was pissed that it wouldnt work. i just wanted my money back!

 

I would find it hard to believe that you got two bad coils in a row.. MSD make a good product, my guess it that they are giving you the incorrect one.

 

are there different ones? i went to my local O'Reilys and they only have one that looked like mine. the stock and the MSD look exactly the same. same brackets and all.

 

Do you need to change your plug gap when using a more powerful coil? Does MSD suggest any parts to change in concurence with the coil?

 

i know if you are running a MSD box like a 6 or 6A. They suggest that you should run a bigger spark plug gap, but i don't believe just with a coil.

 

What distributor are you running? Is it the stock HEI coil inside the cap or the remote coil or are you running an aftermarket

 

MSD has a different gap for use of there products. You should find this in the paperwork that came with the coil, or look online. I had to close my gap on my 91' when I installed my ingnition system (then again, I had MSD control module, coil, wires and distributor too). Also, before I used the MSD distributor, my old one kept burnin up the cap. After about 10K miles the contacts on the inside of the cap would be burnt looking so I'd replace it. I fianally used a premium cap/rotor set. That helped, but it wasn't til I used the MSD distributor that it went away. So check and change you gap, and check your distributor cap/rotor too. Oh and I almost forgot, they say that you shouldn't use solid core wires with MSD products as it will mess the wires all up. You need spiral core wires or something like that. I'd use 8mm wires too.