Golf MK IV 1.6 8V erratic idling

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Thu 5 Sep 2002 10:49
Golf MK IV 1.6 8V erratic idling - st1
At standstill and warmed up my MK IV Golf (1998) with the older 8V 1.6 is idling very erratically. The revs constantly fluctuate anything between 600 - 1000. It's got worse lately but has always done this to some degree. Seems to be OK when the engine is not fully warmed up. No problems with fuel economy or when on the go.

Does anyone know what the most likely problem is or which areas should be looked at first?
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Thu 5 Sep 2002 11:46
Golf MK IV 1.6 8V erratic idling - Peter D
Use a peice of small tube a meter long or so and listen around the inlet manafold and area beneath the butterfly valve. You are listening for air rushing in to the sytem that is not being measured by the air flow meter.

This laek will mainly effect tick over as the air flow in any failed gasket/hole is limited. Running will be fime and fuel usage almost uneffected.

The reason for the viable idle speed is the Cat O2 sensor trying to balance the mixture when air is getting in the wring side of the airflow meter.

Good Luck Regards Peter
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