I had this same problem with the power window switches in my Fiero, which uses the same switch style. It turned out that the new switches were slightly wider than the cutout on the trim fascia. It was rubbing on one side. It did not look like it was until you examined it real close. I was able to detach the switch and then hold it to the opposite side while I tightened the mounting screws back down. This resolved the problem. I know that the Firebird switches mount different, but look close and see if it is the same problem. If it is and you cannot physically adjust it, you might be able to use a light grease on that side too to alleviate the sticking. Something like lithium grease...or even silicone.