QuestionHI Patrick,
Well, both items have been done, both idle speed motor(brand new) and cleaning the throttle body-car has been fine for two weeks and it happened again today on my way into work. No check engine lights or anything, idle just dips-seems like it is going to stall-and kicks back to normal. Foot is always on brake at the time or car is in park. Any other ideas?
I appreciate your time...
Thanks
Lisa-
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Followup To
Question -
Hi Patrick,
I have a used 98 v70 cross country wagon that only at complete stops or at idle in park, the idle will dip to 400 rpm like it will stall and then pick back up to normal again with 5/10 secs. Any thoughts what could be wrong? I just had the idle speed motor replaced with a brand new one. It doesn't do it everyday-maybe once every couple days or when making a quick hard stop. I would appreciate any info.
Thanks
Lisa
Answer -
Hello Lisa, Sounds like its time to have the 'Throttle body' cleaned.Its part of normal maintenance,every 30k,60k,90k miles.What your experiencing is 'idle hunting',trying to find its 'perfered idle RPM'.The idle motor that was replaced does wear out and fail.On your car 'The Body' is a challenge to clean and not just anyone should do it.A trained Volvo person is perfered.Allow 1 1/2 - 2 hrs. labor to complete.The same gum and carbon deposits that took out the idle motor are building up in the Throttle body.Thank you and good hunting(no pun intended)! PKD
AnswerHello again Lisa, Well the common thread is,it happens when 'braking',activating the brake vacuum booster,ie.'power brakes'.When you first push the pedal, you are using a lot of engine vacuum and if the 'check valve' malfunctions,it makes the engine 'gulp',that is 'stumble' before the idle motor can open giving the engine more air to 'breathe',thus the idle returns to normal.With the car in Park,you foot is usually on the brake pedal.Have the booster cheched out as I will research this futher.Thanks again,keep me posted. PKD
