I know this has been covered before but a rehash never hurts.
2006 F-250 with a prominent surge. I came back from the test drive and knew it was turbo related as most 60 surges are. I took command of the VGT solenoid and had to command it past 50% to get the MGP pid to start registering some PSI. Next it was on to a VVT turbo test with the VMM. Here is the result:
From this shot we can see some serious over shoot on the stair steps. This is usually an indication of a fubar'd solenoid. I just happen to have a known good tester and swapped it in and retested:
Much better graph, and a test drive confirmed the surge was gone.