funny idle

[mk2gtimatt]

hey guys i have an 8v gti and she idles funny. when on cold start it revs to about 3k till its warm then drops to about 1500rpm. iv had to alter the idle to this as if i try and lower it it revs to about 2k on cold start but when its warm it will flick between about 500 and 2000rpm. iv changed the idle control vavle but still does the same. could it be an air leak somewhere or something more serious???

and if any1 has a spare 8v pb engine head going im after 1 as my vavle steam seals have gone and itd be easier for me to just replace the head as i cant have the car off the road for too long

cheers guys, any help is appreciated!

[was_ser]

Just to nose in I have the same problem.  Changed the ISV still having idle problem.  I did fit a pipercross airfilter a while ago could this cause the problem?  Also I have a lot of smoke coming out the car so am guessing valve stems whats the cheapest way to fix this ( please don't say new engine) 


Also if anyone wants to find the buggers that broke into my car the other night and rip there heads of with a blunt knife please feel free. 

[Organisys]

Are these the symptoms of a failed blue temp sender everyone ?

[rubjonny]

yes they are, do tell us what year your GTI is


If its a later digifant one, first check the idle switch clicks when the throttle is closed, if it doesn't then take the inlet boot off the throttle boddy and move the idle switch till it makes contact.  I had to tap the bracket with a hammer as I couldn't get to the screws!

Then you have to reset the idle in a specific way:
Run the engine till its over 80 degrees
Disconnect the blue temp sender
Disconnect the breather hose to the PCV (big flying saucer thing on the rocker cover) and block the throttle body side
Rev the engine over 3k three times to switch off the cold running circuit and put ECU into setup mode
Then set the idle to 850-900 rpm, as well as the CO to 1.5% if you have a meter

[mk2gtimatt]

sounds like uv had this problem urself!!! mines a j plate so its the late 1. ill give it a go and let you know how i get on. oh and to do vavle stem seals you have to take the head off and sod about so if you can get a cheap enough head thats ok just replace it! oh and ull need a new cambelt cos ur not supposed to reuse them once taken off, and id advise getting tensioners aswell if theyr not newish, just to be on the safe side! oh and a new head gasket and get the head skimmed.... is it all really worth the cost and hassel???

[was_ser]

  I'll give that a try let you know how I get on..........TBCont.....