I suggest you download a manual for your furnace model. Also there are many YouTube videos on Suburban furnaces, I'm sure you'll find information to help.
The ignitor is ruled by the sail switch. If the fan isn't blowing enough air, (low voltage, blocked air vents) it won't send the signal to ignite. Also, after failing to light, the control board goes into 'lock down' and won't ignite until the thermostat is shut off then on again.
Some of your issues might be the result of the above conditions.
Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI