AC goes 'less cool' when not in motion. Gauge reads overcharged.

Thanks for your response. I was hoping for a DIY solution. AC is new to me but is there a chance this is something for the home mechanic?

I don't know the hi pressure reading. The Low pressure goes into the Yellow section of the gauge that comes with the can of r134. Oddly enough, I ran into a Nissan mechanic while at the parts store who actually put the gauge on the Low cap and told me it was overfilled. I could see that it was in the yellow. Not having put any 134 into the car meant that it must have always been that way (according to him) but knowing the problem was new left me confused.

Cooling less when stopped is a function of less air movement through the condensor. Fans can only do so much.