Whats drops my rpms to 0 and then stalls out when im driving down the freeway?

What is your question?

While driving down the freeway my car desides it wants to drop the RPMs to zero and stall out. It will also do it at a stop light or sighn. It isnt a constant thing it happens once or twice a day then it drives fine. And it normally only does it when the check engine li check t is on. I havent ran the new codes yet but the one that keeps poppi g up is P0446. Any help or advice would be very much appropriated. Thanks for your time.