I'll be the first to admit I know next to nothing about AC's, but just enough to be dangerous and start throwing parts at things.

Both high and low pressures seem high. Guessing it was overcharged when they added freon to make it better. (kids truck that lives 1.5 hours away). Removed some freon (didn't use a scale just guessing) and pressures came down some. High side seemed to fall into range, but low side still seemed high. I did notice that both pressures remained hight until the fan clutch locked up and the fan started pushing air and then it dropped down to a more reasonable level.

Outside temp 100°, low side 62, high side 265 at idle. Rev up to 1500 rpm's and hear the fan clutch kick in, and low side drops to 44 with high side at 290, but the cold air is blowing.

Compressor clutch does work properly at idle and high idle when parked in the shop looking at it. Drove 5 miles down the road and the ac started blowing warm air. Drove on to the restaurant (another 20 miles) and it never cooled back down. Was going to look at the clutch to see if it was still engaged when we parked, but the ac started working again 2 minutes before we parked. Most of the 20 mile trip was with the cruise set at 70 mph. The last 3 or 4 miles was typical in town traffic with 40 mph roads and stop lights. The 2 minutes it started working was a stop light and the left turn, short drive, then right turn into the parking lot.

I did blow out the under hood coil (not too bad). Is there an inside coil that needs to be cleaned? Might still be high on freon, but that doesn't explain it cutting out like it did. I wish I would have just pulled over and looked to see if the clutch was still engaged.

Advice or thoughts of what the next steps should be?