What brand and type of decoder do you have? What scale? Your symptoms sound like a possibly bad decoder, especially if it's an MRC.
Are you running an analog engine on address 00 at the same time? That will slow down the system response time.
Questions:
Carl in Florida - - - - - - - - - - We need an HO Amtrak SDP40F and GE U36B oh wait- We GOT THEM!