2.ltr peugoet diesel no power seems to be off a cylinder

petrol or diesel

I think it's right about 17squirrel power... if it's the 1.6L, it@106Hp

VW diesel engines have a spec of 360-450 psi with new engines. It is only considered a bad engine if the reading is below 276 or there is a difference of more than 73 psi between cylinders.

This is a technique called spill timing line up the timing marks
remove the pipe to the injector on #1 Cylinder loosen the mounting / adjustment bots on the pump attach a spill cut off pipe (looks like a '?") use the lift pump to supply low pressure fuel. While pumping the lift pump turn the injector pump in the direction of rotation until fuel flows freely then turn the injector pump slowly and gradually against the direction of rotation till fuel stops. lock the pump in this position. this is correct timing

your brake lines have a leak somewhere

The engine light is telling you that the cpu has detected a faulty unit that is outside set parameters. Code p0301 is a cylinder misfire detected. Possible causes include Engine mechanical fault. wiring. faulty ignition/ fuel systems., injector. ECT(engine coolant temp sensor)/ MAF (Mass air flow) sensor and ECM(engine control module) I would look at individual coils if you have them --fuel pressure test , head gasket Have a radiator pressure test done

You must ensure the safety of the fuel pump .You make sure there is enough fuel in the fuel filter .
i hop for you the best .

petrol or diesel please be more specific when asking questions

i have been working on peugoets for 12 years and never heard about this
what i would sugest is thet you get in touch with peugeot tech support and see if they can shine any light on the problem

you can try drygas or seafoam at your local auto parts store.