Fuel thief paying you a visit?

Is there a leak when you’re moving?

Wouldnt run right and smoke like a chimney if the belt timing is out. as would crank sensor fault.
number 1 injector sensor failure (clutch end) knocks its bollocks off, only thing i can think of if not a leak is an earlier type egr with choke flap wrongly plumbed for vacuum, closing up and strangling the engine. makes em really slow though

Thats a serious leak tho. check top of injectors for damage to leak off pipes

I can build PSA Dw8’s in my sleep 😉 Theres 2 on my bench as i type
The belt can be pinned up in the timing holes fine, but if the verniers are not done correctly according to model year (2 types -verniers on cam and pump, or slot on crank and verniers on pump) as you tension the belt it can go out by even a couple of degree, dependent on which way it goes you either get diesel knock or smoke. Advanced by a midges and they run quiet and clean to the eye, but exhaust temperature runs off scale and you get EML lights and EGR faults. MPG goes up a tad in that instant tho

Has it been serviced recently.

Ie has it actually been serviced . Does it have a new filters that you know have been done a d not just the guy that sold it yours word.

What is it idling at ?

Is it topping out about 65ish on the Speedo ?

Hows the oil level ?

Mines returns 38mpg no mater what. I’ve had 2 now. Even on the autobahn at 85(max speed really,)

As Ulysses says slightly advanced and it runs hot with eml on . If you retard it by one tooth it knocks it’s tits off and you think the cranks gonna shatter.

Filters and egr.

Egr fault and you’d know about it, when they stick open it sounds like the head gasket has gone and smokes for england!!

Sticking shut is fine and i’ll often disable hi milers in to a stuck shut state

Look next to the air filter box for the air plenum connecting to the EGR assembly, its a ClicR clip so you’ll need pliers for, or get creative with some nippex cutters unless its already been swapped for a jubilee worm drive clip. Its a 3″ dia assembly. look if it has a vac actuated flap at the very end, see if this is remaining open when you rev, when it sticks shut it gives the same symptom as soma described for a choked air filter.

On a 05 plate it shouldnt have that kind of “flap” system, but they do fit the manifold of all these engines, so a bodge by a previous owner could see one fitted