Volvo V70 D5 rough idle

My Volvo 2004 V70 D5 diesel has developed a rough idle. It's got plenty of miles on it (227k) but otherwise is running fine. I suspect this has
gradually got worse but I only noticed it yesterday for the first time, and the engine cut out once while sitting in traffic with a 'Urgent engine service required' (or similar) message on the dash. It restarted fine and hasn't cut out since.
I've not been able to read the fault codes yet, as I'm away from home, and the reader isn't with me. I notice that the engine shakes more than it should when idling with the bonnet open, and it sounds like the idle speed is wandering a little - but not enough to show on the rev counter.
I notice a small puddle of liquid around one of the injectors and it's more grubby than the rest (small leak?) but not enough to be worrying.
The car is serviced when it asks and generally is run on decent fuel, however the previous tank was supermarket stuff.
I suspect the electronic throttle body may need cleaning, or a vacuum leak. Apparently the vacuum engine mounts can leak on these.
I've cleaned up a throttle body on a petrol V70 recently which cured it's idle issues, so hopefully this is the same. I *do* have a tool kit with me so will get come carb cleaner later and see what I can do in the hotel car park tonight!
Any other suggestions or things I should look at?
Alan.
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Certainly clean the throttle body, and EGR valve, which at that mileage will be very caked up....
How does it start from cold? The misfire could well be an injector on its way out, which will be leaking back and often the tell tale sign is extended cranking when cold, and/or a worse misfire for afew seconds....
Tim.
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This evening I have removed the 'T' piece from the EGR valve output, and the hose from there to the input manifold. Both were fairly caked in black gunge, so I have cleaned them with carb cleaner (in Halfords car park!) so both are now clean. The EGR valve output is a bit dirty, but not as bad as I was expecting. I've not attempted to remove that yet due to limited tools / facilities where I am.
So far it seems much the same.
There doesn't appear to be a throttle valve - pipework appears to go: Air filter > MAF sensor > Turbo > Intercooler > EGR 'T' piece > Manifold.
Cold start-up is usually fine, but occasionally (maybe once a month) I get a rough start where it appears to only run on 2 or 3 cylinders for a few seconds then dies. Always cured by switch-off and re-start.
Home tomorrow (~200 miles) so hopefully it's OK for the journey - but at least this fault seems to only affect idle. It cut out again today (before clean) when trying to pull away. I'll read the codes tomorrow night and report back.
Would a restricted EGR valve cause idle issues? Or maybe it's an injector or two getting tired?
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Without looking at the car, I would suggest an injector getting tired, however, I would also advise a compression test before you start flinging injectors at it just to be sure of the overall condition of the engine- and then an injector leak off test both hot and cold for both...
Tim..
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OK, drove home with no issues and read the codes:
P0244 - Turbo wastegate solenoid P0087 - Fuel Pressure too low P0094 - Fuel leak detected
I cleared the codes and took it for a drive. On booting it it came up with 'engine service required' and went into limp home mode (2500 rpm max). Code P0244 returned but no others. Cleared code again and after lots of booting no codes on return.
I've trawled the forums tonight, and it seems P0244 is the same as Volvo code ECM6805, which can be caused by vacuum leak issues, especially in the front vacuum damped engine mount. These are disabled past 1500 rpm which certainly fits my previous symptoms. The mount is easy to bypass, so will do that tomorrow, and see if the issue re-occurs. Next checks will be the turbo control solenoid and the turbo control actuator - I believe it's a variable vane type.
No ideas on the fuel pressure issues, or how long those codes have been there, so will ignore them for now, unless they return.
MPG is unchanged, and no oil being used, so don't think it's a compression issue at this stage.
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Alan Deane wrote:

I had a Vectra in once that kept coming up with several codes (inc. waste gate and egr valve), I eventually traced the fault to a crack in a vacuum actuator for the inlet swirl flaps. The way I traced it was to find out the level of vacuum with everything bypassed (so right at the pump) then reconnect bits (the vacuum should stay the same except for momentary drops when things operate) After narrowing down which side of the engine the fault was, it was easy to find the dodgy bit, and close examination actually showed the fault. Why they can't put in a 'low vacuum' sensor and give it a fault code is beyond me, it would have saved me quite a bit of time.
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I've found a localish stockist of a vacuum tester, so will get one of those today which should help track down the issue, and prove if the turbo actuator is working properly.
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Alan Deane wrote:

you do need a gauge, since it is impossible to judge by 'hiss', I had one from the old days of carbs and distributors, first time I had used it in years.
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On 03/08/2012 11:42, Mrcheerful wrote:

Its looking like my issue is defiantly the front engine mount. I disconnected the vacuum line to it and blocked it, and have driven it for a bit (including idling in traffic and booting it) and no further issues, or codes logged. Only side effect is more vibration transmitted to the car when idling.
Looks like an aftermarket one is about 85 delivered, waiting for Volvo to call me back on a price for a real one. Tried GSF, they dont stock it.
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On 03/08/2012 14:18, Alan Deane wrote:

Follow-up: Engine mount vacuum line plugged and no further faults logged during the next 200 miles. Ordered replacement mount from Volvo (103). Fitted yesterday and driven a further 50 miles today, no faults since, and back to a smooth idle. 800 mile drive coming up at the weekend (all towing) so that will give it a decent test!
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On Tue, 07 Aug 2012 22:52:15 +0100, Alan Deane
Bastard sitting there waving its fist at you?
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On 08/08/2012 01:04, Grimly Curmudgeon wrote:

Yep!
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Definately eliminate the front engine mount boost leak or whatever, the plastic hose often breaks or rubs, giving a leak. I dont believe it is disabled over 1500rpm, the whole idea of it is that turbo boost is fed to the mount which stiffens up against the torque reaction of the engine under power.
This still leaves your misfire etc... If the throttle body is VERY gunked up with carbon, you could well be finding yourself removing the intake manifold itself to clean out, as I have seen the actual ports 1/2 choked by carbon on some engines...
Tim.
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