C5 2.2HDi 'hunting' problem

[Citroenmad]

I've got a friend with a 2002 2.2 HDi C5 auto. It recently developed a fault which resulted in it displaying ASR and anti-pollution warnings. That was tracked down to the swirl vacuum which was replaced. Replacing the vacuum solved the problem and it has performance like it never had before. However, after fitting that the engine now hunts and runs very rough on idle and at low revs, worst on idle. It's almost running on three.

I've checked it with the lexia which had the following codes in the injection menu:

Inlet air temperature signal. Short circuit to + or open circuit (P0110)
Flowmeter signal. Short circuit to earth or open circuit flow too low (P0100)
Dust filter overloaded. (P1448)

All are temporary faults which have been cleared but the running problem remains. It has not stored any other faults.

Interestingly the average distance of the last 5 DPF regenerations was around 340km, its now down to just 68km ...

The injector flow corrections on idle read:
1: -2.47
2: 5.14
3: 0.27
4: -2.94

Which doesn't seem totally right ... it also smells quite diesely from the exhaust.

Any advice appreciated

[DickieG]

Blocked DPF and/or duff MAF sensor is where I'd start looking Chris.

[SaabC5]

I'd agree on the blocked DPF