307 2.0HDI No boost wont rev past 4000Rpm

[Ryansworld]

I have the Peugeot 307 2.0HDI 136Bhp model. The problems Im having is lack of power like there is no turbo at all. Also when starting from cold it hickers and struggles to rev. Turning engine off the back on and the engine revs better but wont go past 4000Rpm. I changed the Turbo vacuum solenoid and it was reving all the way but still lacked some power. However yesterday It went back to square one. Struggling to rev wont go past 4000. I am getting codes read next week just curious if anyone else had these symptoms. Much appreciated.

[Bick]

Total guess but try unplugging the MAF sensor and see if it improves - although not a guaranteed diag method.