Ive got the same problem too. I get the stuttering when my car is under load in high gears at low rpms. If I go WOT though it basically goes away, but once it did it and it felt like I hit fuel cut, but I know that cant be it. Oh and my car is also backfiring out of the intake. I havent changed my plugs in a while like I used to so Im going to do that, and change the fuel filter since it hasnt been changed for 80,000 miles