I can sit in driveway and pump pedal and it wont do it,but when i go down the st and stop at an intersection for a second the pedal wont come back up unless i pull it up with my foot and its hard to pull back up..booster problem? It idles fine no vacuum leak,replaced master about a yr or so...al

 

If your brakes work fine(no leaks or air in the system), then you should start diagnosing the brake booster.

 

it idles way to good to have a vaccum leak,brakes work great..looks like a pain to change it out,my chevelle has the studs on the outside,these are on the inside..