Scotty i got a Ford Fiesta 1.0 ecoboost with 125.000 kms on it , my turbo disables itself when i accelerate hard at around 2500 rpm it cuts out and i have to restart the engine for it to work again , when i unplug the vacum from wastegate and put my finger on it , it doesnt hold steady vacuum it feels like it's pushing and pulling air. Also the wastegate rod has a constant tremor. Ford doesn't want to replace only the wastegate and they only sell the whole turbo assembly which costs alot to buy and replace. Also my engine is running 25% too lean and the only codes i found with a OBD scanner were P0444 Canister purge valve open circuit and P0458 Evap system , evap valve - circuit low and no codes regarding the turbo problem. 

I was thinking of buying one of those vacuum testers to check the tube that goes from the solenoid to the wastegate and then check the solenoid itself and the tube that goes from the vacuum pump to the solenoid.

Any help appreciated !