 My 2007 4 cylindercamry has always vibrated in drive with the ac on when stopped. This is how the dealer handled it. First we changed to name brand high test gas. Then we had multiple computer adjustments to 750 rpm at idle. In a short time it dropped to 500 rpm and back to the vibration. Then they did a top engine cleaner at a cost to me of $100.00 now they they say I need a new throttle valve assembly that is defective at a cost of $1000.00 dollars. Toyota will pick up $500.00 but alas it's out of warranty! P. S. Toyota awful. Never again