Unsettled Revs On Tick Over

[Guest 20dizzle5 gti]

hello my 205 gti that i just finished rebuilding the engine and started it up ad when it sits on tick over i let it get warm and set the idling speed to 10 on the rev counter when the engine was warm but the revs will slowy creap up and drop back down and this keeps happening but i think the old 1.9 cpu is still connected will this have anything to do with it thanks hope u can help

[Anthony 1,003]

Check the idle mixture - if it's running rich, it'll tend to hunt for revs as you describe. Try turning the mixture screw on the AFM anti-clockwise a couple of turns and see if that improves matters at all.