revs up and down aaaarrrrrrrgh!

[craig o gti]

got a mk2 gti 8 v wen stoping at traffic lights my reves go up n down and some times stalling iv tried a new idle vale but still the same  if i  put the smallest of revs down runs fine? any 1 help please

[gixer1400]

hi did you buy one of those new idle valves on e-bay for about £55 ?

sadly they do have problems too i had to sent one back as it was doing what you've

described  reving up and down

send it back and ask for another you may get a better one   

otherwise try a 2nd hand bosch one or a new one from gsf ( about £210 ) 

you could check the rubber hose at the bottom of the valve for leaks as this too will affect the tick

over .... good luck

[nealey]

Check for airleaks first before sticking another idle valve, you may have to take the grommet out of the camcover for the breather and check it as sometimes they split along the seam and they are difficult to see.

[h8v]

...and also check the two cables leading to the plug on the ISV. 

They sometimes break where they go thorough a tight bend, and flex with the movement of the engine.

Took me some months to find!

h8v

[rubjonny]

check idle switch clicks when throttle closes, and the wiring to it hasnt snapped behind the inlet