I'm not sure what engine you have, but I have a '92 Saltare with a 454 and the Pro-Tec ignition system. Your going into limp mode. This is a feature of the Pro-Tec system. If all of your gauges are reading in a normal mode, it's probably a switch thats gone out. You have three that are the main culprits.
My engine is doing the exact same thing, although mine @2000 rpm. I called Vince at Skidim, and he walked me through how to troubleshoot the system. If there is anyone out there who knows more than him about that system, I don't know who it would be. Its probably a simpler fix than you think. Those switches aren't very expensive either. Good Luck.
2005 24SSV
5.7 Indmar 340hp