Wandering revs...

[P11GT]

when below 3000rpm, my revs have a +/-400rpm wander on them.

this tends to die down a little after a service, but it's always done this since I've had the car (about 10k miles).

Anyone have an ideas what could cause this, or is it just a characteristic of the engine??

The ECU codes are clear and I've checked the TPS and Airflow sensors.

The ECU can adjust the idle at different times, ie you will notice
that the revs may hold for a few seconds after slowing after a
fast run, this is to burn off excess gases in the catalyst.

Ah yes, I've noticed this. The problem seems to be slightly more than this, though.

If I'm accelerating, it's not a problem, but if, for example, I'm trying to drive in 1st gear, holding the revs constant, the car buckaroos all over the place, as the revs bounce around.

Basically, it's impossible to hold a constant rpm. Not a problem in 3rd gear upwards, but a real pain when in 1st or 2nd.

thanks

That sounds more like the EGR valve req's cleaning, if u have a look
there is an old thread just on this subject, apparantly its easy to do, but I've never done one !