Fault codes-
P1622 throttle valve position/ intake manifold pressure invalid ratio
P0105 intake manifold pressure sensor signal improbable
? Camshaft position sensor outside set range

This car originally came in with a shredded cam belt which we replaced with what appeared to be no engine damage ( the belt was on just loose and stripped)
Recently it developed a cutting out issue which was evident for a couple of weeks then nothing? now when stationary there is only servo assistance once due to manifold vacumm between 650 Hpa- 800 Hpa.
There is also a slight misfire when cold which is when the vacumm is at its lowest this we think is due to the ign coil (due to a suspect waveform-pico) and will be replaced shortly. Once warm there is no misfire and the vacumm does improve but not to an acceptable level? No visible air leaks (will be borrowing a smoke machine to make sure) suspected maybe the throttle valve to open what with the faults logged but the butterfly is almost shut at idle and actuator test moves through open to close fine (although a bit jerky?) have checked manifold pressure with gauge and it mirrors actual value with a steady needle.

What kind of layout does the breather have on these, can it leak internally?
Any idea what i should be looking at or a crucial test i've missed. Any info greatly recieved thanks for reading.