I just finished analyzing my $935 bill for my 100,000 mile service and the dealer's attempt to correct the hunting idle. The dealer thinks I "may" need another new throttle module. The last owner did this in 2003.

The specific things the dealer did to try to correct the problem this time was to replace the IAT sensor (intake air temp sensor), the ECT sensor and thermostat (coolant temp sensor), and performed a bunch of software upgrades...(....and unlike Microsoft...volvo charges for the software upgrades.....but I'd be happy if it fixed the problem.)

I'm just looking for a little advice here in case anyone out there can tell from my symptoms if its really the throttle module....or something else.

The car starts fine, and DOES NOT HUNT until it warms up. The hunting at idle increases in variation as the engine warms up, reaching a peak of 500 to 1000 rpm. Looks like it is going to stall as the rpm drops, but then the engine increases its rpm to 1000 then drops and the cycle contines. No hunting at all when it first starts when cold. Other than the idle issue, the car runs very smoothly....there is no variation at driving speeds. The performace is great, it doesn't burn any appreciable oil, the gas mileage is great. The car is a 5 speed, so the reduction in idle speed is not a serious safety issue. The car has only stalled once due to the hunting idle.

Does anybody have any thoughts on what to do next?