2007 Peugeot expert van "jerking" and poor Fuel consuption

[Finnishman]

Hey all! I need some advice with my expert that what could be wrong.

While driving under 2100 rpm there is some "jerking" while The engine is on low load. It's most noticiable when driving around 90km/H with 5 or 6th Gear and trying to maintain steady highway speed. When i accelerate the van There is no jerking. The jerking feels like that the engine is starving of Fuel for like 0.5 secs and then returning back to normal. The cycle will continue like every 5 seconds. There is no fault lights on.

I also think that the van uses more Fuel than it should use (around 9.5-10L/100km when there is no AC on, driving calmly and The car is empty).

[moizeau]

Unplug the maf and see if the problem goes away

[Finnishman]

Unplug the maf and see if the problem goes away

The problem did not go away

[moizeau]

In that case it needs plugging in to a good diagnostic machine then. Not a cheap multi marque one, they can't get all the codes.

[Muir]

One thing you might be able to check with a cheapish OBD scanner dongle is whether fuel rail pressure is steady at a given RPM.
Could be a dodgy fuel pressure regulator though that doesn't explain the increased consumption.
Since the problem is not present when accellerating it's probably not the HP pump nor the lift pump.

Either way try plugging in a scanner and see if it throws any fault codes or get a readout of the rail pressure when the jerking happens.