This oven starts to heat up, then stops heating. I replaced the Hi temp t-stat but, it does the same thing. I even jumped the wires, but nothing different. What am I missing?

Here are your parts
Parts for KitchenAid KERS807SSS02 Range - AppliancePartsPros.com

See the attachment for the tech sheet

[COLOR="Blue"]This oven starts to heat up, then stops heating. I replaced the Hi temp t-stat but, it does the same thing. I even jumped the wires, but nothing different. What am I missing?[/COLOR]
I am not sure what you are referring to as a hi temp t-stat. Could you identify which part it is on the wiring diagram in the tech sheet.
Also what wires did you jump.I need more info on what it does when it stops heating. Does the display shut off, does it show it is ready when it is not, does an error code come up, etc. , etc.?

[COLOR="Blue"]Well, according to the factory rep, the oven has too many bells and whistles to handle the self-cleaning mode. The board fried.[/COLOR]
Could be a bad board you will not really know till you replace it.
Depends on the symptoms.
Could also be a bad oven sensor depends on the symptoms.
Could be just a bad solder joint on the board where the oven sensor attaches to it.

I am assuming that this problem only occurred after you did a self clean.
Did the cooling fan come on when you ran self clean?

I would go after Whirlpool and ask why they sell a unit with self clean when their factory rep says that it will damage the unit.