I've got a new, low-pitched VIBRATION...

[STORMIN08]

based on the decel, and braking response, i am leaning more towards a faulty sensor...ie, map, maf, iat or the like. possibly dirty, or even a little out of whack on calibration. does it do it woth the BB tune, or even before in stock form, hopefully someone with a stock vehicle will chyme in, i will try to simulate this in mine, but i only have 1300 miles on it, and i have 3.42 gears.
do you have an intake of any kind, cat back, or any other performance items ?

ok, so i spent a good part of this morning trying to duplicate this, i can hardly get 30 mpoh, and stay at 1000 rpm. but , i have no chugging.....even able to set the cruise at the this speed, and nothing for several miles. i would say it is probably a fluke sensor, that is a little out if calibration, it dosnt take much. as far as the vibration, i would look heavily at the rear u joints.

 

[KMeloney]

Thanks for the feedback, Shawn.

 

[KMeloney]

do you mean even when braking the rpm's still go up a little like the trucks still accelerating? Mine seems to do that at low speeds/parking.

Exactly. For instance, my driveway is pretty level, though there's a small lip at the base of it, and it's just long enough from the sidewalk to the garage to accommodate the Tahoe. I'm just @ 50 yards from the nearby intersection. When I come through the intersection, at @ 20 mph or so, I brake at my driveway to pull into it and to avoid hitting the lip too hard. When braking and turning into the driveway, the rpms will inevitably dip and then flare up above 1500 rpm, making me feel like I'm going to be pitched through the windshield. Either that, or the rpms will flare and kind of float there in such a way that it feels like the tranny is free-wheeling, making me apply the brakes a lot harder than normal (or it feels like I'll crash into the garage). It takes way too much thought an effort to try to feather the brakes to avoid the harshness of either situation. I can't stand it.