Pretty good chance you will damage the multimeter connecting it to the high voltage side as most are not designed to handle that much voltage. Your talking 6,000 -10,000 Volts plus on the plug for it to fire. Your best bet is to get a spark tester or use a known good plug with the base of it grounded to the engine block and look at the spark. Should be strong and blue. If thin and week or no spark then you know you have a problem.
:ditto: You'll ruin the multimeter for sure! As Mark said, you should go by color. Be careful to ground the plug safely and hold it by the rubber boot, though! Some ignition systems run at up to 25,000 volts!