C5 tick over help

[paulkirkin]

I have a C5 2.2 Hdi auto and posted this problem several months back. Several dealer visits later, I still have the same problem.

When I stop at lights, the engine idles smoothly for about 5 seconds then goes rough and shudders intermittently every few seconds, as soon as I accelerate is smooths out again. This only happens when the engine is hot, now the weather is cooler it takes much longer for this to begin.

EGR has been mentioned many times as the possible cause so I have tried the following experiments:
Unplugged the EGR control valve mounted on the bulkhead.
Blanked off the exhaust feed into the inlet manifold.
Both have had no effect at all! I must be missing something here, can anyone please tell me exactly what occurs when EGR operates, the ECU must be doing more than opening a valve and letting poor quality air into the air intake!
I'm at my whits end with this and can only think of trading the car in, any suggestions please!

[KevMayer]

How old is the C5 and how many miles has it done ?

What do Citroen think it could be ?

This may give us a clue about possible suggestions.

Cheers, Kev

[paulkirkin]

The Car was manufactured in May 2005, it is still under warranty and has about 17,000 miles on the clock. Citroen say it is probably the EGR but is within spec. They have stated that some vehicles do this worse than others and that mine isn't particularly bad. I have owned a number of Citroen diesels before, and they all had a smooth tick over. Do we have to accept poor running as a consequence of emissions controls?

[paulkirkin]

The car was made in May 05 and has done 17,000 miles. Citroen say the misfire is within spec and some cars do it worse than others!

[wheeler]

I presume citroen have updated the engine ECU & autobox ECU's software

[curly]

I had a similar problem but mine had rough tick over when cold then was fine when hot ,turns out it was the injectors .Have they checked them?