Hi All,


I'm hoping to resolve a long running idling issue with my 1999 Caravelle. RPM at idle is around 850 - 900 until I turn the air con on . The drop is then to approx 350 - 400 RPM. I have had many garages look at this for me and everyone has put there $$$$$'s worth in to it. The best result so far was having a VW mechanic basically retune everything so that the ECU was able to run properly. This did make a big difference and increased the idle speed slightly however it is now back to normal. This makes exiting roundabouts risky as there is a chance of stalling and hill climbs have to be done with the air con off. Could this be an issue with the throttle body? I ask this as even with the air con off it really struggles up hills (its a 2.5L Petrol) - should it be struggling? I have to mention as well that the air con unit flashes for approx 10 secs when being turned on and although it works ok then the heating only comes on when the setting is on HI , cooling is ok it just doesn't blow all the time.


I'd also like to mention that when the ignition is switched to the firs setting (before starting engine) there is a clicking noise in the engine bay. Could this be the sensor on the throttle body not working?


So far the following has been done:
Air Flow Meter replaced
HT leads and distributor replaced
Various tweaking of idling settings


Thanks


Simon