Checking the coil?

["Michael E. Blair" <mblair@nfis.com>]

Is there anyway to check a coil? I am trying to eliminate my problem with my
car running bad after about 20 minutes of driving. Car runs fine, 20 mins
later it is popping and missing terrible. Park it, let it sit for 15 mins
and it runs great again.

I am thinking maybe the coil is breaking down after heating up and not
providing adequate spark to fire properly. Any tips on how to prove or
disprove my theory?

Thanks,
Mike

78B