MW hunting during Base load trial in Gas turbine

power generation take in Mark V frame 6. Once in a month base load trial is take otherwise run on part load. all the parameter is normal during part load except GCV opening is sluggish. now problem is that when base load trial is taken MW hunting start.

also problem is that when base load trial is taken that is IGV opening is 84 main lube oil tank vacuum deteriorate. tank level drop and oil droplet come from mist eliminator. Please solve my problem