So my 93 Formula came equipped with the factory keyless entry option (AU0) and I have both original transmitters. I programmed them to the car as per factory instructions and they never were quite.... right. They were finicky with how they worked, sometimes they were fine and sometimes they wouldn't work at all. Even when they worked, they wouldn't work very far away. I'd have to be standing at the door for them to register and work. I tried replacing the batteries in the transmitters and there was no change. Eventually they just stopped working and I could not get the receiver to get in to programming mode to try and sync them again, so I just left it alone. Then I came across another 93-95 F-Body with the option at a pick and pull and snagged the receiver unit from it, swapped it in and it basically went just like the first time. Everything programmed fine, but it wouldn't work very well. Found a used one on eBay from a lower mileage car and swapped THAT one in. This one looked pristine, no dust / dirt and the board looks good on the inside. No corrosion that I could see and everything looked great. Same story when I programmed it. It works, but over a few weeks the range has diminished all the way to where I have to stand at a certain angle and push the button in just the right area over the windshield and it works. Is there a way to boost the antenna on these things? Anyone mess with these? Here is a picture of the receiver:

 

I'm told that holding the remote fob under your chin will increase range. I know it sounds stupid and I've never tried it myself but the theory is that you head acts as an antenna. I would try it in an isolated area with nobody around - what have you got to lose other than having people laugh at you? If it works, come back and let us know. If it doesn't, nobody has to know you tried.

Seriously, have you considered that the problem might be with the fobs rather than the receiver? New fobs are available online for not much money. It might be worth getting one and seeing if that makes a difference. Bear in mind that the keyless entry in these cars has never had much range... even at its best, mine wouldn't work from more than about 20 feet away - many times not even that far.