One problem related to engine stall has been reported for the 1999 Toyota Sienna. The most recently reported issues are listed below.
A design flaw in the engine caused the engine to develop sludge, this is when the oil turns into a thick tar like goop that clogs the engine a oil systems, when the vehicle was take to the dealer it was stated that the only cause was improper maintenance which voids the customers warranty, there was no warning or indication that the engine as about to be damaged, the consumer had to have a new engine installed in their new vehicle. Nlm.