I think I have a plugging up orifice tube on my friends 03 F150 truck, what do you think? Symptoms: clutch cycles about every 1.5 seconds, pressure on low side 25 at kick out 40-45 at kick in, high side kick in about 125-140 kick out at 175 (75-80 ambient). High pressure line from the orifice tube to firewall covered in ice, low pressure line out of evap. is warm, slightly cooler than ambient. With heater hose clamped off I get 60 degrees at low fan speed, center vent, recirc. Un-clamp heater hose and temp slowly rises to 70 degrees (about 10 minutes). During the short time compressor is on the low side drops and the high side rises much quicker than I would expect, hence I suspect the orifice tube is mostly plugged. What do you think?