95 850 Sweden, stagnating motor

Christophe · Post by **Christophe** » 18 Feb 2005, 12:06

While driving down a hill or driving at low speed the motor starts to stagnate. The motor also loses power when I take over or start to drive. At the garage they have no idea what the problem kan be. Maybe you know what the problem is and how it can be solved.

Regards

Christophe from Sweden

White850Turbo · Post by **White850Turbo** » 19 Feb 2005, 08:02

By stagnate, do you mean the idle is rough or the engine acts like it's going to die? Is the lambda light on? Have you checked codes ? Is this a turbo model?

Christopher · Post by **Christopher** » 21 Feb 2005, 12:46

Hi,

Thanks for reply, I'm sorry, my english is'nt very good.
If the engine is on idle, the rmp goes upp and down, from 700 rpm
to 1500 rpm. No Turbo.
No failure codes, no lights on the dash warning. Lights work when starting the car, so there is no bulb failing.
Tomorrow I'm going to the volvo garage again. I let you know...

rainman · Post by **rainman** » 22 Feb 2005, 15:32

Possible answer to the 700-1500rpm idle problem would be your IAC (idle air control) motor which adjusts the air/fule mixture at idle adn compensates when the motor is under load (e.g. when you turn on headlights/wipers/heater) at idle.
Only other solution i can immediately think of is malfunctioning ECU, but this would normally throw codes. First thing to do though, is to make sure the car is breathing properly. Go back to basics and check airflow through the air filter, clean the flame trap out and oil/crankcase breather pipe. My car was hesitant like this for about a month and it was a tiny blockage in the inlet manifold, combined with a blocked flame trap (Volvo made the flame trap too small and hard to clean on the 850). Hope you get it sorted.