Previa Surging when a/c is on. Please help

[x2cy]

Hey Guys. So im having trouble with a/c. It blows cold but when im driving (at highway speed) I can hear the relay click on and the van surges. Now i understand the van will surge a bit due to it being a 4 cylinder but this surge is happening every 3 seconds or so. Way more then normal. Idle up valve is good and working as well.

Any help would be great

[originalkwyjibo]

Sounds like your refrigerant level is low.

[x2cy]

Sounds like your refrigerant level is low.

Thanks. I will try that