My a/c would work intermittently . It seemed to cool fine while driving . When I come to a stop the truck would seem to lunge forward and stop cooling . After a few seconds it would lunge again and begin to cool fine . I took it to the only place that has done a/c work on it and was told they could not duplicate the problem . Really I don't think they looked into it much . This was a year ago so I just haven't been using it .
My truck 94 f-150 , 5.0 L , still runs very well with good power at 197,000 mi. . ???

 

Try a shop that specializes in AC shouldn't be hard for them to diagnose.

 

The shop I used in the past is A/C business . They did good work for me in the past .

 

Try another shop anyway.