Idle issue

drew525 · Post by **drew525** » 09 Jul 2009, 17:56

Hey everyone
So I posted on an issue similar to this in the past but am still having a problem. My 850R still seems to have a bit of a rough idle. The problem only seems to occur when in park, the engine seems to start to shudder a little and the rpm will drop, the rpm will then increase to keep the engine from stalling? Also, I'm not sure if it is related but the engine fan will kick on and off while this is happening.
The plugs, cap, rotor, alternator, and wires have all been replaced. I've cleaned out the throttle body as well.
Any ideas?

Post by **Ozark Lee** » 09 Jul 2009, 19:51

Yank the codes even if the CEL is not on, Volvos will post codes without setting a CEL. My bet is a bad ECT sensor.

...Lee

drew525 · Post by **drew525** » 10 Jul 2009, 20:57

Probably should have mentioned that both the therm. and ect were replaced in early spring.
Checked codes but there weren't any.

Post by **Ozark Lee** » 11 Jul 2009, 00:56

I suppose the next thing to try is a compression test since you have covered the basics. When gas got real expensive last year many folks quit putting premium in their turbos and the result was burned exhaust valves.

I must admit that I am among the folks that went to a mid-grade fuel on the turbo but anytime I knew it was in the tank I drove like my mother-in-law - except that I didn't hit any other cars in the process.

...Lee