My 07 GS 350 seems to not like to have the a/c on while the engine is warming up (I live in Vegas where a/c is required). When I'm in Drive / idle, the rpm needle will sometimes jump up and down as if the engine is fighting to not cut off. I have to drive for a bit until the engine is fully warm and then I'm able to turn the a/c with no problem. I have also noticed maybe once or twice that even with the a/c off during the warm up, it can be a bit sluggish after switching out of reverse to drive. Any ideas what could be causing this? I've only had the car for about 10 months and it has about 130k miles on it.

 

i posted a similar thread 3 weeks ago, i too notice Vegas heat DOES affect the car performance greatly, so i gave myself excuse and drive down to LA for anime expo beginning of July and MY GOD my car freaking punch when i tap on the paddle,

anyway to answer your question, 120+ heat is really thin for car engine to suck in, take a drive to Socal sometime and you can tell how much air your car nee,

i drive a 07 GS450h 120k miles btw, not much differences than yours