# Mk1 CIS K-Lambda idle hunting



## Hoffa (Jun 7, 2001)

I have posted about recent issues I am having after re-instating a Lambda system on my US 1984 Rabbit Gti with CIS in the Mk1 forums with really good feedback. Details are in my VWV thread here along with pictures and video and my testing so far.

Basically, open loop works as it should but when it goes closed loop my duty% is swinging way out of out of the +_8% spec @ along with a hunting idle and sometimes almost stalling. I've tried a second new O2 sensor, tested the VREF, checked for vacuum leaks, thermoswitch tests good, idle boost valve clicking, frequency valve is buzzing as normal. Cold starts are no problems & otherwise off-idle and under full throttle it runs very well! 

My next steps are checking timing and fuel pressures but was curious if anyone here chased this issue with success or have some other things I may be missing.

Thanks,
Hoffa


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