These engines don't last. They have a known fault. Listen to your engine running on tickover. Can you hear a tap, tap, tap sound coming from the top end. Also can you here a womp, womp, womp sound. If you can, take the air intake pipe off the air filter housing. Is the deep sounding womp, womp, womp louder. Sorry I have sone bad news for you. A rocker arm bearing has collapsed and is preventing some valves from working correctly. Stop driving the car. The valve can get jammed open wrecking the engine.
Replaced all 16 rocker arms, timing belt, water pump, glow plugs as one had failed. 2 of the glow plugs would not come out so the head had to come off. Got parts at trade. All in all with labour £2000Edited by: Timbo