Lumpy idle

Just wondering if anybody can help me, have a 03 1.9 tdi passat, which has a lumpy idle when cold, warm, and hot. Lumpy idle is even there wether the clutch is depressed or not, seems to be there constabtly. There is no lose of power or reduction in fuel economy and lumpiness is not there when reved over 1000 rpm. No fault codes when put on vcds.
Any help would be very much appreciated, it has 242,000 and is only used for commuting so I don't want to spend much money on it hoping for a cheap explanation

thanks for the reply, I forgot to mention that this only began in the last 1500 to 2000 miles would a cam shaft show wear this rapidly. Two people have said cam timing the alternator clutch pulley and the injector loom cause this to happen is this true, my alternator clutch pulley is very loud

sio, are you using the Air Conditioner? If so, try turning it off (and everything else too) at idle and see if it returns to normal non-lumpy operation.

sio said:

...my alternator clutch pulley is very loud

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Replace it and get back to us.

Never used the air conditioning I live in wet Ireland ha ha, it's lumpy at idle with no power usage, saying that if I have the lights on at night and if I'm idling at the lights for example they flicker, think the alternator could be the cause

rydogg said:

sio, are you using the Air Conditioner? If so, try turning it off (and everything else too) at idle and see if it returns to normal non-lumpy operation.

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Mine does the same thing, but only when the a/c is on. What does that mean?

sphoppie said:

Mine does the same thing, but only when the a/c is on. What does that mean?

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Ha! I wish I knew, I just assumed the AC is loading the engine (unevenly). I'm not too concerned about it...but maybe I should be

Well I'm glad I'm not the only one