Shuts of when put into reverse

This may help: http://www.toyotanation.com/forum/274-2nd-generation-2004-2010/199861-04-sienna-transmission-lock.html
There are multiple issues here.Won't crank? Go direct to starter.

Possible recall:http://www.toyoheadquarters.com/threads/2004-2005-2007-2009-toyota-sienna-shift-lock-solenoid-recall-d0r.206/

possible that the sensor which senses the gear selector position is going bad.

Its likely the electronics and sensors inside the tranny.
Take it into a reliable tranny shop and pay for a diagnosis (only).

Need transmission repair. Sorry.

The shifter cable has broken more than likely ,Find the shift shaft on the transmission,,block the wheels and remove the shift cable from the shift shaft,put the gear shift in park,then shift the shift shaft in park,then it will start,Then of course you will have to replace the shift cable.

Could be fuel filter,air filter,tune up,wires,coils.low idle too low.

The engine uses an air flow meter and any vacumn leakages would cause the engine to shut off. I would suggest checking the air hose for leakages, hidden cracks that would only appear when the engine is shifted into reverse.

When in forward gears, the engine would tilt to one side, there are no leakages but when shifted into reverse, the engine tilts the opposite way, ( old engine mounts tends to allow the tilting to be quite substantial) causing the air hoses etc to open up any cracks and allowing excessive air to leak between the air flow meter and throttle body causing the stalling.

Hope this helps.

Have your transmission oil filter changed;
it is located under the transmission pan
The oil is what makes the transmission shift
When you shut off the engine it stops the transmission pump then when you start up again the transmission shifts until the filter clogs again

you need to check the wires from the shifting lever, when you put it at reverse a wire is caught at the mechanism creating a short circuit that makes it shut off the engine.

its in the timing ...whenever you start it it sits and idles fine but when you go to put it in gear it dies...the timing needs to be repaired. its a guaranteed solution.