min RPM shifts,,,

[basstard]

Hi guys, got this problem on my TDi 110 SE:
sometimes the minimum rmp shifts from normal 900 to 1100rpm,,, just dunno why. It only goes back to normal when it wants (usually after a minute or so), no matter if standing still or movin', no matter if the engine is hot or cold,,, btw the car's been chipped to 13x hp,,,

[mattjex]

I had the same thing on a previous A6 1.9tdi 110 that I owned (was superchipped with K&N profile to 148bhp on RR!!, but this only happened if there was a direct draw on the engine, i.e climate up high, heated seats.. this kept it up around the figure you say

weirdly if the headlights were on dip, and you put electric windows down, this would set it up to 1100, but it would usually come down straight away..

Other than this, sorry no ideas.