Q&A

You might have a dirty condenser coil or blockage between the radiator and the coil. This would not let air flow through to help cool the coil, when you are driving more air gets through and as the coil cools so does the air in your vents. But there are several other problems that could cause the same result, like a weak compressor, blockage at orfice tube or expansion valve. You really need to have a performance test done on the system to pin point the problem. Just adding freon yourself or scanning for codes will cure this problem. Replacing the A/C clutch doesn't require replacement of the dryer but replacing the compressor does.

most likely u have a leak and are wasting money on freon. the sealer is a temp fix at best. find the leak w/ a/c leak dye and repair as req.

If the freon level is good (A/C clutch is not cycling on and off all the time) and airflow is continuous (the fan is not shutting off), then I would check to see that the A/C clutch is engaged when it is acting up. It's common for the clutch to shut off when it warms up, probably from an open electrical circuit inside the clutch.