I had been having issues with a fluctuating idle which were largely solved by fitting a new lambda sensor.

However, I still have a weird blip in the idle (only 50-100rpm) which is preceeded by a little click. It sounds a bit like a relay switching or something? Often the idle will "click" back to the previous level after 15 secs or so.

Does anyone know what could be causing this? I'm thinking maybe electrical - grounding, alternator?

Any help much appreciated as ever.

Cheers
Freshtripe

 

Sure it's not the aircon kicking in? The compressor doesn't run continuosly and I hear a click from the drivers well as it starts. The compressor puts a fair load on an idling engine so my guess is this is what it is - switch off the aircon and see what happens then.

HTH

 

Thanks Trashman - I had a suspicion it might be that - I'll brave the high temps wihtout aircon (!) to see if it still does it...

 

Could also be the Radiator fans kicking in. Even without the aircon, these represent a fair electrical load, and on earlier cars you'll feel the engine revs change when the ECU switches them on. And a nice relay will accompany the switch on

 

Hi freshtripe.

according to a local dealer the air con may cause a problem with idle with air con on! Hope it is this. Keep in touch with the idle thing mate.