Harman Accentra distribution blower shuts off

We have a somewhat drafty living room where the 5 year old insert is in the fireplace. The distribution blower shuts off periodically and we can't seem to get the room as hot as we used to. I have done all the maintenance and cleaning. All original parts still. I have cleaned the ESP probe previously. I want to be able to set the stove so that the distribution blower never shuts off and maxes out the heat to the highest possible extent.
Currently...
Temp: 7/90 degrees
Feed: 5
Igniter: Auto
Mode: Room Temp - High
Thermometer is about 6 feet away from stove and the actual room temp gauged by our central heat thermostat on opposite side of the room is only about 67 degrees when it is 40 outside today. When it is colder outside the room may only get to low 60's. In the past, we have been able to get the room to the low 70's.
I'm trying to think all about this logically, but without having full knowledge of all parts.
The igniter does sometimes seem to lag a bit when lighting in the morning, but I don't think that would cause a problem with the heat output once it gets going. Although the blower operation is intermittent, the blower doesn't seem to make noises like it is going bad, but I'm not sure. My logic is telling me it might be the instructions from the system telling the blower to shut off.
Our budget is tight, so I don't want to spend money on parts unless it is really necessary. I have done a lot with computers and hardware, so I feel I could change almost any parts without paying a dealer. In speaking with our dealer, they told us they would need to take the stove back to their shop if the blower or system board needs replacing...I don't like this answer...do you feel it has to be this way? (I feel like they may be trying to ramp up the labor charges.)
What are the best settings to keep the blower and heat output high?
If I can't get the distribution blower to stay on constantly, what parts would I consider replacing?
Where are the best parts prices/reputable dealer online or to call to order?
Thanks in advance!

Thanks for the info so far...

P38X2, Our dealer is a small operation, they installed it and they will come out to service it.

MSmith66, By "baffles" do you mean the heat exchanger panels? I cleaned the ESP which really wasn't dirty as I cleaned it near end of last season. I cleaned everything else again, which also wasn't too bad because I cleaned it all last week trying to resolve this issue. Also tried Stove Temp high and feed rate of 3 and it still cycles off the blower. Do you think I need a new ESP? I can get one online rush shipped (they're calling for 4-6" of snow tomorrow with a cold week coming) I feel like I should order it fast.

Harvey Schneider, I vacuumed everywhere else I could and I didn't see clogged vents or lint and we have no animals.

Found an ESP at a dealer 20 miles away...swapped it out for $69, but it doesn't seem to be the problem...I had to start somewhere. Now I'm thinking I need a new board (which was my original gut feeling) Any thoughts?

replaced ESP...replaced board...no change in problem.
Solution - cleaned the distribution blower fan.
If you've never done this before, it probably needs cleaning. It is underneath the unit. I pulled the stove out and (with help) laid it on it's side onto some couch cushions and an old blanket. I found a massive clot of lint, hair, debris, wrapped into the intake, which undoubtedly would not let it run properly. Afterwards, the stove ran like new.