I have a fairly new but very lightly used front loader Whirlpool Duet
that has always served me well, but has gradually not dried as well as
usual. Due to circumstances it uses a flex tube to vent. I removed it
from the dryer and tried it, assuming there was a clog in the vent
(although the vent does seem to push a lot of air). I got warm air,
reconnected the vent and tried to dry a load, no luck. Removed the vent
tube and cleaned it as best I could. This morning, it was able to dry a
load.

Any suggestions for easy to use diagnostic choices? I dread paying for a
service repair, but do want my dryer back in working form