Shutter when AC Compressor clutch engages

[kriticalchris]

I drive a 2007 Volvo s40 2.4i. Recently when I start the car the AC doesn't kick on for about 10 minutes of driving. What's strange is i can "feel" when the clutch engages there is a noticeable shutter, or stutter. I've checked the low pressure psi and it reads 40psi when the clutch is engaged. I've also tried jumping the pressure switch. It also seems the clutch engages when I leave the fan speed on max waiting for cold air to blow. And it doesn't cycle on and off once it starts to cool ot stays that way until I turn the car off for several hours. Any thoughts or Input?