99 Tahoe Pings Need help

Hi, I have a 99 tahoe, 70k miles that pings when acelerating.
Does't ping when maintaining a speed.
Also runs rough on idle sometimes. Very strange.
I have tryed all different kinds of gas. High test, different brands.
I installed Bosch platnum plugs and new wires.
I have used injection cleaner.
I have changed all filters.
Last thing I tryed was a knock sensor. The part that is located on the passenger side of engine block.
That was the last thing someone suggested. Actually I think it got worse after that.
I'm am at my wits end with this and I have never had to take a car to a dealer to get fixed before and I really don't want to this time either, but, I feel that if I don't find any other ideas that make sense it must be a computer thing that I don't know anything about.

Anybody have this happen before.
Thanks,
JC68GTO

Vacumm leak somewhere??? TBI gasket? Intake gasket? Hose? Timing off?

Spray some brake cleaner around and check for a change in engine speed.