I took it for a drive this evening with the thermometer in the dash. It bottoms out at 47F in 82F weather with 70% humidity. When stopped it shoots back up to 58F within a few minutes and holds.
I can see the high side pressure on the Torque App. It fluctuates between 190 and 230, but roughly centers around 205 PSI. According to the chart above that is in range.
But still.... 65F air coming out of the vents (which is what the spec calls for according to the images I attached) does not feel all that cool at 90F with 70% humidity. In fact at that temp you can feel the humidity returning to the air coming out of the vents.
I checked the outlet from the evaporator and it was dripping pretty fast, creating a decent puddle under the car. So that's not the problem.
I feel like the chart above was made to prevent warranty AC issues and AC can get much colder than that at proper charge.
I'm thinking of just biting the bullet like you said and grabbing one of those cans. Then I can see both low pressure (on the can) and high pressure (reported by OBD port) and get a much better picture.
Maybe I'll just spray some in and see if the temp drops at all...
