Some quick questions. On your turbine have you tracked your TGT to see if there has been a significant increase, on its idle temp. If so the compressor blades might be degrading therefore causing the compressor stall to occur when a load is put on the turbine. Remember most of the air going through a turbine is used for cooling if the compressor is not working correctly you will see an increase in TGT, compaired to what it was before.