1.6 tdi p0299 code

Hi there, new here, i’ve been a fan of the skoda brand for a while now and have always stated that they’re “bulletproof” well now i think that statement up for discussion.....i have a 1.6 tdi 16 plate octavia and recently had the error code p0299 with the glow plug light flashing and limp, seems to be 2500 rpm or higher when it occurs aslong as i stay under that theres no issues.

 replaced MAP sensor

replaced vac pump

replaced MAF sensor

tried spraying mr muscle into intake side of turbo as thought up by a friend

no obvious signs of splits in pipes or whistling noises.

now i am requesting the help of the wider community please, if anyone has any advice i would very much appreciate it thanks.