Booked in to dealers on Friday for diagnostics. Fuel consumption is up as well, only getting avg 23mpg on long runs.

Hey wait I thought for a mo you actually had a petrol V6 what with 23mpg...
Mine has a slight flutter on the power and I've got to back it off, if I don't engine light comes on temporarily. Car still useable thank god but it still rains...
Anybody into Anti-rain-dancing.

After nearly 4 months, 2 main dealers and a local garage having no luck with sorting this, including a main dealer trying to tell me it needed a new boost pressure sensor for £186, which I had replaced 2 days before.. I took it to the excellent Clive Woolford Motor Engineers in Tewkesbury. They had it for half a day, at a labour rate less than half the main dealers and found 2 faults. I was getting the P0235 BP sensor error code and also P0487 which I think was EGR related. They found one of the thin vacuum pipes to the EGR valve had a hole in it due to chafing and the EGR was clogged up. More obscurely, they discovered that the loom to the ECU had at some time been refitted so it was routed incorrectly and fixed with cable ties, such that it was under tension and so making intermittent contact, which may have lead to the B Pressure low voltage error?

The car now goes like a train and is back to it's old performance and the fuel consumption seems improved.

it's nice when you find someone that is actually capable of diagnosing faults and not just swapping parts out.

Regards
Richard

Nice result Jodel, may help me there somewhere. I'm on a P0235 and it causes power loss on booting it. But it started to shut down as well but a new sensor at £53 cured shutdown only. Have still to get vacuum pipes to EGR and Turbo checked out. But be interested to know where this ECU tight cable work is.

Having sorted the Boost Pressur Sensor and loom problems, I subsequently got a loud buzzing noise from under the bonnet, which would continue for about 30 seconds after switch off and then die away. The mechanic at Clive Woolford diagnosed it as a failed diaphragm in a pneumatic solenoid which operates some sort of air valve used to shut off engine. It doesen't appear in any of the sensor diagrams in the PDF diesel-SM manual I have, which led me to think it is a later addition connected to emissions? It sits at the front of the head, to the left of the Boost Sensor and is fed vacuum as a branch off the EGR vac solenoid and outputs down to the shut off valve near the EGR. It looks very similar to the EGR solenoid and is made by a Czech company called Pierburg, part no 7.01010.00. I have got one on order.

Anybody shed any light on this please?

Sounds like the throttle valve. It is to do with emissions and it blocks off the air to the engine when the EGR operates.

Richard