So many thing it could be and as your finding you can end up just changing everyother bit till its fixed. Idealy needs to be driven with live data recorded to see whats going on.

Check all vacuum pipes for splits. Check turbo boost pipe for splits opening up when on boost. Check turbo actuator etc. Presuming the 90 hp has a turbo of course. Chris diesel to the forum!

Have you asked/searched on French Car Forum?[/url]

Hi, try driving the car with the air flow metre disconnected, the idea being if the air flow metre is disconnected the Ecu will revert to internal mapping for air and fueling. Also depending on age there is a vacuum control throttle valve on the rear of the engine that can stick on light throttle or low rpm.
I’ll have a think or any other issues.
What’s the last 8 of the vin no?

Slight thread hijack, I replaced the air mass meter on my 2002 2.0 HDI C5. There was a huge improvement in immediate torque and acceleration. Soon after the performance went back to its slow coach mode. It wasn’t that I became accustomed to the improvement. When you fit an air mass meter is there any other reprogramming required? I simply switched the old part for the new one.

Morning, not looked at the tuning box web site but my feeling is “cheap” chip boxes that mainly just re route the fuel fail pressure and tell the Ecu it’s lower than it actually is are a very poor way of increasing power, and generally cause smoking/over fuelling and seen one blown engine, proper remapping is different again but expensive and without being rude it’s not a sports car.
Let me have a look today at the known issues and the type of system on the car.
E mail me trout wrestler

Mcmoonter – you have a fault somewhere else on the car. Try getting the fault codes read. Was it a new MAF you fitted?

Yes it was a new MAF, Ive tried two now. Pricey at about £80 each.

I’ve not got a fault code reader. Is there anyone in Fife you could recommend?

OBDII readers are £7 on ebay, they work just fine, software for them is also easily picked up off the net. Then get a list of fault codes and go through them..

I’ve had a boost pressure sensor go on a Passat; there was a hesitation thing going before it became an obvious lack of turbo boost as symptoms got worse.

Maybe an o2 sensor, now that its in limp mode get the codes read.

It should have one maybe two.

I had a 2.0 HDi picasso (probably the same engine) and the throttle cable was slack. there is a clip you can take the tension up with. Worth a shot.

I get the low rev stutter on my 407, same 2.0HDi engine. As it’s only used for long runs/occasionally I’ll live with it until whatever is causing it properly dies, especially as the throttle position sensor (generally acknowledged as the most likely cause) is hidden in the pedal box and a nightmare to get to on mine…

sounds like a bit like a problem with my audi which turned out to be an intercooler leak