2005 Chevy Tahoe with 5.3l, everything is stock & Non flex fuel 5.3l. This has been an ongoing problem for some time now, when i first accelerate from a stop(stop light, stop sign) my Tahoe will try to accelerate for a split second at first and then make a growling noise and almost stall(doesn't die) at almost every initial acceleration from a stop. The noise seems to be coming from under dash maybe firewall/pedal area. When it starts to stall like this if you take your foot off the pedal and push again right away my Tahoe will will accelerate like its supposed to and on to the next stop sign/light and starts all over again. You can feel it in the pedal when it goes into this growling mode sometimes, its almost like a pulsing in the pedal. Has anyone else ever had this problem or heard of it? The only thing that i can come up with is maybe a bad Pedal Position Sensor, TPS, or Steering Wheel sensor. Any Ideas out there?