hi - first time poster, owned my townhome for a year now and am handy
but this has me puzzled:

my gas furnace has not been starting when i've turned up the termostat:

i turn the temp up a few degrees above the current temp, the furnace
turns on, and the "whoosh" doesn't kick in, so the furnace (fan?)
clicks off a minute or two later.

earlier the "whoosh" did start and the furnance started warming up and
moving air, but clicked off about five minutes later.

i've reset the breaker, and thermostat. this problem is on and off,
worked fine on sunday, but didn't work saturday and today.

my furnace does not have pilot light, says it "automatically ignites"

i had a cleaning last year, so i'm due for another one and was planning
to call my local company, but just curious what to expect, or if it's
something simple i could reset

i've also googled "furnace, whoosh", and seen some previous answers
about cold air from vent blowing out pilot

thanks very much in advance!! i'm in colorado and it's mild temps
right now, but want to solve problem before it gets cold again.

i appreciate it