The airpump on my RX7 FD3S year 1996, works only when the engine is cold. However when it attains its normal temperature the Airpump stops working and the idle is crap. Any idea why?

 

It's been a while since I had emissions but sounds like normal operation of the AP. If you haven't yet, download a copy of the Factory Service Manual from the 3rd Gen Stucky thread at the top of this section and check the emissions section.