1991 Riviera Keyless Lock Problems

Just replaced a remote that I lost a few months ago. The old (original) remote would unlock/lock both doors just fine. However, the new one seems to have a little trouble doing this, requiring several key presses to lock/unlock. The power door locks function just fine using the in-door buttons. I'm wondering if there's a seperate relay for the keyless system that might be dying? It seems like you have to hold down the remote button for quite a long time as well. The interior light and trunk lid release work just fine. Any suggestions?