Engine dies when a.c. is turned on!

[citp38614]

I have a 2005 Tahoe. When I crank it, it runs until you turn the air conditioner on. I have cleaned the throttle body out. The check engine light was on when I purchased it 3 weeks ago and I had a tester put on it and it was a knock sensor. Since this issue occurred the check engine light has went off. Your help will be greatly appreciated!!!

 

[Gsxrracing1]

Not sure about this issue on your Tahoe however on my old mustang, when i turned the AC or Defrost on and the AC compressor came on it would bog the engine down to the point it would shut off. Long story short it was the compressor that had gone bad. May be worth a shot to look into that