Our Estate Super Capacity electric dryer is heating erratically. On "Timed Drying" dial settings it won't heat at all but on the "Auto-Sense" settings it does but will sometimes require two cycles.

1. We clean the lint filter before every use and I clean the vent grill periodically.

2. The vent hose is a pretty long run, about 25' horizontally, along a garage wall and out through the rear wall. It's been that way all along for years and not a problem in the past.

3. I have long suspected the coils were getting weak but don't know how to test them or if they can be replaced easily.

Any tips would be appreciated.