Popping releif valve. Takes stopping and shutting the motor off for several minutes for the limp to go away. The old cycle the ignition 3 times trick doesn't work in that case. I should shim it, but it only ever happens when my fuel filter is bad. The engine keeps calling for more and more fuel and it keeps ramping up....eventually too much.

http://www.pacificp.com/pdf/45-06%20ShimKit%20Installation%20Guide.pdf