Surging/pulsing when in 2nd and 3rd Gear

[technophile]

Hey guys,

I have this weird thing with my 06 TD5 where when in 2nd and 3rd gear i occasionally get this surging thing happen. It happens when i am doing a constant speed, generally when on flat or slightly down hill roads; and stops if i depress the clutch, or accelerate.

Any ideas? It may happen once or twice a week.

[uninformed]

are you backing off the throttle at the time?

[technophile]

Yes, not like foot off accelerator, but slightly.

[uninformed]

Could be driveline backlash??

[BilboBoggles]

My TD5 has done this since new. I believe it's a feature of the EU3 ECU map that comes from the factory. Only happens on very light throttle where the engine cycles between a little bit of fuel and none at all. A remap would fix this, but I've never bothered.