My Volvo 960 idles low and rough. The diognostic code is PO172. (fuel too rich) it's either too much fuel or too much air, according to the auto part store. I think it might be the intake manifold gasket. Is this accurate, or am I missing something?
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1996 Volvo 960 Question: low and rough idle
Answer #1M_Kast April 03, 2010, 21:09Journeyman
An intake manifold gasket implies a vacuum leak. It is possible that there is a vacuum leak, but there are some other things that could be wrong as well.
2) O2 Sensor
lawrenceg April 04, 2010, 23:38Master
A leaking intake manifold gasket is very common on this engine. The way I find it is to get a water bottle and spray a stream of water around the intake runners where they attach to the head. They normally leak at the ends,, near the #1 or #6 cylinder intake runner. If the gasket is leaking, the engine will stumble when the water is drawn into the cylinder from the vacuum leak.