My 97 C280 has been sitting awhile. I have a fully charged battery (13.38 volts) nice warm day. She cranks over, I hear the fuel pump energizing from the rear, slight smell of gas in engine bay so it appears fuel is making it through.
I haven’t pulled a spark plug yet. What is the best visual way to check for spark? At night? Or with a voltmeter?

( two months ago during the winter I tried starting her up… long cranks of about five seconds… she did fire up but only for a few minutes. I didn’t use the gas pedal as I should have and she just idled to a stop) thought it might be cold weather but apparently not. Also the gas seems good or she never would have started I think.