Hi Everyone. I am new to this forum so be gentle please.I own an A4 b5 1.8 which my better half uses (i am a landrover man myself). Recently whenever you come to idle it is erratic for 10 to 20 seconds then steadies.Recently replaced spark plugs and air filter but no difference.Checked all pipes and wiring connection i can see all looks ok.I am thinking a dodgy sensor somewhere but not sure where to start (ECU whats that about the only electronic thing in my disco is the clock ).Any pointers greatfully received. Cheers

 

you could do a throttle body alignment, which might help. but if the idle steadies after a few seconds it could be something with fuel delivery, like bad filter or dirty injector. does it run right in the high revs? are there any codes stored in the ecu?

 

dont know anything about ecu codes never having delt with them.As for running seems absolutely fine to me its just when you pull up to stop and it drops to idle.Does it hot or cold even straight on start up.

 

Had the battery disconnected lately? You have to do a throttle body alignment after you loose power. That teaches the ECU where the throttle is so it can control the idle.