Umm! trouble with Idleing

[speedy gonzales]

People,

When I start my gti (8v) it revs to 2000 and then drops right down as if its gonna stall, then it picks up again to 2000 and it continues to do that until i get bored and turn the engine off and go inside for a cuppa tea!

The blue temp sender may be at fault as when I push down on the connector wire it starts to rev a bit higher.

Would you suggest changing the sender or change the connector lead

Thanks guys, oh and wrap up this winter's gonna be a b!tch'n!!!!

Speedy G

[Agreeable Slick]

might be wanting to check your idle stabilisation valve aswell, or rather give it a clean, its generally these that cause most idle problems.

[Alpha98]

i had a vr6 that did this, i spent a fortune on new sensors, idle control valves, coil packs and everything else people recomended, VW's computer found nothing wrong aswell. turned out in the end to be damaged/burnt piston rings?!

[Mr Blue]

change or fix the connections on the blue temp sensor.

look for air leaks. cleaning the ISV is a waste of time. Look for damaged vacum hoses and check the rubber bung ontop of the rocker cover. The bung seals the oil breather to the rocker cover. yours might be split which is common

[rubjonny]

Check the idle switch clicks when the throttle is closed.  On the MK2 8v its underneath the throttle body, you have to take off the inlet boot to get to it.  Plus the screws are almost impossible to get to unless you remove the throttle body, so I tapped mine with a hammer till it move enough to click when the throttle is closed.  No more hunting idle for me

[VR6_ROB]

i had this problem on my mk2 8v thought it was isv valve but it was'nt found out they was some broken wires at the rear of the engine behind the accelerator bits so i plugged them in n it stopped

[Organisys]

Check the idle switch clicks when the throttle is closed.  On the MK2 8v its underneath the throttle body, you have to take off the inlet boot to get to it.  Plus the screws are almost impossible to get to unless you remove the throttle body, so I tapped mine with a hammer till it move enough to click when the throttle is closed.  No more hunting idle for me

They can still be faulty even if you hear the switch go click. On mine the actual contactors in the switch are working intermitantly, sometomes the idle is fine , other times it is too high (isv not kicking in). A blip of throttle is needed to persuade the switch to work.
Not been bothered to fix it yet, cox as you say need to remove throttle body.

[speedy gonzales]

Thanks guys,

Does the above fit in with the fact that when i rev the engine, the revs come back down slowly!!  I have been running in circles in looking for an air leak (but cant find any), ive changed the rocker cover, the gasket and the  rubber grommet that lies on top of the rocker cover. 

I have now ordered the blue temp sender and connector wire (so i can work over it on the w/end).  Does anyone know of any person i can go to to get this sorted (any one in Essex) if i dont manage to fix it?

Appreciate the help guys

Speedy G

[Organisys]

Does the above fit in with the fact that when i rev the engine, the revs come back down slowly!! 

Yes. Mine does this also when the switch is not working.
 

[kkh120]

I've been chasing a problem like that for ages. Blue temp. sensor changed fixed my revving problem but it still stalls on occasion. If you track down your problem let me know.......please!!!!