CB , Nestor is making an important point and it's great tip. You can eliminate all the parts youve replaced. By disconnecting the dryer you are eliminating the vent pipe as a cause.
If you have a defective timer or humidity sensor in the dryer running it off the vent should help this show up. But if your vent happens to be plugged or the exhaust fan underneath the dryer the moisture backs up and your clothes don't dry as well.
In my first experience when I ran the dryer on timed cylce it woked. On auto cycle it failed beacuse the auto cycle senses humidity and shuts down the load. So I replaced the humidity sensor and all was well.
However on another occaision several weeks later after cleaning the entire vent system, one of my toddlers jamed fabric softenting towels under the lint screen and the dryer wouldn't dry again since they sucked into the exhaust fan under the dryer. We found the screen on the floor and figured it had just dragged out the door with a load of laundry. But when we put it back in and ran more loads the blockage caused the moisture to back up. The dryer would run, the element was freshly replaced and still no go. I spent a couple of hours ripping it apart again checked the element, etc then realized there was no exhaust pressure underneath. Check your fan and your vent just in case.