Yeh but that's irrelevant to the power loss right? What should be done?

 

Go back to stock..... RE-DYNO stock... Then install exhaust.. RE-DYNO.. Then install headers.. RE-DYNO..

Other than that, there is really nothing else that can be done..

~ Joe Z

 

I would bet that you don't have a problem, and the variance is due to poor control of your study.

Use another method to evaluate the performance gain, ie a run down the drag strip and compare your trap speeds.