Rough idle due to HVAC turning on(?)

[invent4hir]

Over the past 3 weeks while stopped at a stop light I notice that my idle drops to about 350-400 RPM for a moment then rebounds. This is quite noticeable as the SHO feels like it’s going to die. The dealership checked it out and said this occurs when the compressor is turning on. That seems logical as it appears to be true when only when the HVAC is on. However, in the 3 years prior I don’t recall this happening. Has anyone else had this experience? If so, any solution(s)?

 

[RedCandySHO]

It should drop a little but not to the point it feels like it is going to stall. Take it to a different dealer.