I have a similar problem and complaint on a 90 Reatta.
(I'm going to do it as soon as I feel like curling up like
a hermit crab and getting into the Reatta underdash
In my case, and I have researched it quite well, the fix is
to disconnect the keycode reader leads to the
key pellet, and solder in a precision resistor of the correct value.
This will substitute the correct resistance value every time
you try to start the car, and you wont have to try to replace
the code readers, etc.
Let me know if you need more information.