Sounds like air. I chased a similar problem and figured out it was my harbor freight gauge set. Once I replaced it it no longer was running at high pressures.

I get 50f vent temps while driving in 105F ambient with 55psi low and 340psi high at idle. In the mornings at 80F ambient I can get 38F With r134a.

With your ambient I would aim for 35psi low and 280 high at idle.

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