mk3 16v problem

[AdamBeevers]

Ok, so i've searched and searched ad searched. I bought a 2.0 16v the other week and it had a few problems, plugs, leads, oil and oil filter have all been replaced.
The problem is the car wont idle, i start it up, and have to keep revving it to keep it running (sketchy to drive) and sometimes after a while it will just about idle (after the revs dipping right down then back up to about 9rpm)...

when its cutting out too the rear lights dim down loads and a battery light comes on and it cuts out all together, its not the battery as i've tried a friends and it didnt make a difference, could it be earthing or something? The car is an old rust bucket so anythings possible!

As much help as possible will be great, i'm off to euro parts now and will check my phone once i get there to see if any updates have been posted!
Thanks in advance!

[big_G_622]

first thing i would do is go on the search thing at the top of this page. loads of stuff on here for that subject.
first thing on abf engine to check is vacuum hoses - firstly the one from back of the inlet manifold to the ecu. 3mm id silicone is the best as it wont collapse under heat. easy to change about 30mins work.

next you got your fuel pump and ecu relays. always cause trouble

earths can sometimes cause trouble give them all a good clean

isv -also try cleaning

throttle body - cleaning

list could be endless..............

none of the above work. plug into vagcom check you got no errors 

[AdamBeevers]

okay cheers will try the above

[rubjonny]

does the battery light come on with the ignition then go out when the car is started? if not the blue wire from the alternator has snapped somewhere.  the idle issue sounds like a problem with the isv to me, but do easy n free things like clean the throttle body and check all over for split hoses in particular the one to the ecu

[mk3bummer]

lol. all my valvers did this apart from 1. yh check those things and you should be cool . what is it with vw and idling lol.   crazy