Ford fiesta 1.4 tdci 08 problems!!!

Hi All, 

Where do I start 🤔.

So over the last year and a half I've had 2 injectors changed 1 and 4 with a garage due to power loss first they claimed it was no.4 but problems persisted took it back they then claimed it was no.1 (personally I think they just changed the wrong one at first) car ran to a degree ok for a while.

The problem came back and more there was the immobiliser locking up the car wipers and hazard lights coming on and the engine management light came back and went into limp mode obd2 claimed it was the mass air sensor. (Changed) at the same time I replaced the fuel filter and the car was good again for a while. 

Engine power problem came back it was suspected that another injector needed changing so I had injector no.3 changed (when changing we found that one pin in the loom had been bent into the same slot as the second pin) it was ok again but it was venting gas (hissing noise) so when I had the cover off I changed the last injector (injector no.4 had the black death and im convinced was never changed) cleaned and reseated the bore changed all seals top/bottom, copper washers and fuel drain off o ring. All sealed and no hissing! I thought that would be it but NO! ENGINE MANAGEMENT LIGHT (HIGH PRESSURE SENSOR FAULT)

I had the car diagnosed on a snap on scanner in a garage who recommended i change the sensor. So that was changed with the recommended part but it didn't have one slot in the plastic housing that matched the electrical connection. After confirming with the supplier that it was the correct part I removed the tab from the electrical connection but I'm still getting a warning light and fault from the sensor.

After all this it was suspected that it was wiring loom all along! So I went to my not so local car breaking yard and got the loom from the connection to the injectors, hpf sensor and glow plugs but this has not fixed the problem and this is where I'm at and loosing the will to live 😑. What have I done wrong or missed. I hope someone can shed some light 😵‍💫