I have an idea: your car doesn't use "freon" .. It uses 134a. Which isn't "freon". Haha......... My guess it is still low on "refrigerant". The reason it gets cooler when driving is cos the compressor is working more than when the motor is just idling. And the fans are suppose to come on with the a/c. Those gauges in those do-it-yourself a/c refrigerant charging kits aren't that accurate. Need to connect the hose to, IIRC, the high side. Start car, turn on a/c at maximum, then release refrigerant into system rotating can the while time until the air gets cold, this is how I do it, and it has worked every time. But, if the system is low on refrigerant (134a ) then there's a leak somewhere.
Last edited by Ercmann; 05-20-2013 at 06:58 PM.