86 with a miss fire problem

[joebuck]

im looking at buying an 86 GN with 82k on the clock. The owner has told me that after 15 mins of driving the car starts to miss and backfire. He says he thinks its starting to over heat so he shuts it off and allows it to cool for 15 mins. After restarting the car has no problems. This doesnt sound like a cooling problem. I want some opinions on what this may be.

 

[MY T FAST]

i'm biased bc i've gone thru so many of the damn things, but that sounds like a bad coil/module to me. mine always miss/break up under boost at first, but as you continue to drive it, it'll start to miss under vac/cruising conditions too. it could honestly be a plethora of things, but that's where i'd start considering these cars' tendency to eat coils.

aside: good news is that bc its intermittent, its highly highly unlikely that its something internal (cam lobe, etc.) as that would likely present itself all the time.