Vauxhall Vectra C 1.8VVT

Petrol z18xer engine
169k Miles on the clock.

Lemme explain. when i bought this car it had a cam sensor issue turns out it was caked in build up i swear the old owner barely serviced it. so after removing the sensor and cleaning it the car ran fine, with the yearly service.

5 years later and a couple services late im experiencing a power drop, cars fine then suddenly power drops alot until i off and on the car again. same error code on the scanner. cam sensor. ive changed the oil and even though it doesn’t drop its power as much (it happens randomly) i’ve tried new sensors and removed the rocker and cleaned the cam sensor areas (was caked), same thing. leads me to believe. theres alot of build up gunk in the engine.

i think im gonna risk a engine flush and a full service.
has anyone ever experienced engine failure with an engine flush you add to the old oil?
people talk about how bad it is etc but no one i’ve spoken has seen a car die from one.

Thanks in advance