DC2006 slow printing and copying

[DC2006User]

DC2006 will print at the posted rates for some of the time but at other times it will take up to 3 or 4 min to print a single page. Sometimes recycling or cancelling all jobs and resubmitting them will correct the problem. The machine seems to be cycling repeatedly during this time. There is a noise that sounds like it's rotating the color cartridges followed by fan start up and shut down. After this happens several times the printer then prints a page and starts over again.
There are no error codes and the toner and print cartridge have been changed with no effect.
Any suggestions as to what's happening?

 

[DC2006User]

Following up on this post. I bought a copy of the 790/2006 service manual and spent a bunch of time trying to figure out how to read it. Used it to take the machine apart and clean it.
There was a whole lot of waste toner inside the machine. There is a tray inside called the BTR2 Assembly that was overflowing with waste toner. Emptied it out and cleaned it up. Curious thing though. Although, it collects toner the machine doesn't clean it and there is no maintenance reference to cleaning it. Cleaned out the water toner tube.
I then re-assembled the printer and it now prints quicker most of the time but it still experiences the delay
discussed above sometimes.
The service manual is directed to solving error codes and has no discussion of the printing process or printing problems (such as slow printing). Anyone out there have any info? or know a source for this info?
David