I also have this problem with my dryer. I have replaced the transistor - it worked for about 4 weeks, I have "reformed " the wave washer - it worked for about 2 weeks. I think the act of opening the blower motor (splitting the case), and putting it back together is what caused it to work for awhile.
I can't see how the encoder flag and pickup could get out of alignment, without destroying itself, it has to be a tight alignment for the armature to turn.
I don't see how the transistor could work sometimes, and sometimes not work, causing the blower motor to work intermittently.
I guess I will break down and buy a new blower motor and hope for a permanent fix.
Anybody have any other ideas?
GE harmony profile dryer model # DPGT750EC2WW