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Robert
Robert, UK Qualified Car Technician
Category: Car
Satisfied Customers: 4366
Experience:  Fully qualified / self employed garage technician in the UK
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2008 c4 picasso excl - fully service history 75k a week ago

Customer Question

hi there
2008 c4 picasso excl - fully service history 75k
a week ago the engine became a bit weird
it is not smooth anymore
it is shaking when cold but even when it's hot it is not smooth. Changing the gear is not a problem it is something like a valve is not performing or something like this...any idea?
Submitted: 2 months ago.
Category: Car
Expert:  Robert replied 2 months ago.

Hi..there..

2 litre petrol or diesel you have?

Any warning lights or messages in info screen pop up since this occurred?

have you had any recent work carried out on the car?

Customer: replied 2 months ago.
Diesel
No fault message and norecent work apart from oil chnge and mot 2 month ago
Expert:  Robert replied 2 months ago.

Hi..there..

If your refering to sticking valve causing compression loss resulting in missfire..is one possibility but it would be hard to actually diagnose that without getting a proper compression test done on all 4 cylinders to see if thats the case or not then leading to leak down test to see which valve is at fault..not easy on the HDI's as you would need to test via the glowplug orifaces and removing them would need some care to avoid snapping..removing injectors can be tricky especially if they are siezed solid in the head.normally you need to hydraulically pull them out and even that cant be guaranteed if the cylinder head gets damaged....going by what your saying id be leaning to a possible injector fault a mechanical spray problem..check to ensure the oil level hasnt increased due to overfuelling .. to check injectors you would need to get those tested,leak back and such before any work is done..id say that would be your first step from here..most well equiped garages should be able to perform that test and see what that brings up..

Customer: replied 2 months ago.
hmmmm
took it today to Citroen garage this morning and they were saying that it caused by the dpf (i think) filter and they recommended some fluid to add to the diesel before I take it to the motorway for a 30 mins ride. If it does not work I had to take it back for a diagnosis and service. I will give a go to the fluid first and will let you know whether the problem has been sorted or not.....
Expert:  Robert replied 2 months ago.

Normally that would come up as an "Anti pollution fault" having said that If the DPF was restricted you have a severe lack in power leading to cutting out..but you would have warnings up to verfiy that aswell as fault codes...added to that your car would likely have an Eolys additive fluid thats already injected into the fuel to help reduce DPF issues...If the car is missfiring severely both hot and cold as your describing to me..giving it run like that wouldnt be advisable in my opinion

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