Hello,

I own a year 2000 model manual S40 1.6 (bought in Hungary) and it had this problem since the beginning but it's now getting worse so I need to do something about it.

On hot days, when the A/C is working heavily, the rev goes haywire. When stopping at a red light, it should be idle but instead it changes between idle and 2500-3000, it sounds as if I'm challenging the neighboring car for a race. This year it also already happened several times that the rev falled so low that the engine has stopped, that's why I said it's getting worse.

Similarly, when moving slowly in a traffic jam, I have to keep my foot on the klutch, because sometimes it decides to attack the car in front of me. It is also impossible to slowly roll by fine-controlling the speed in 2nd gear without using the clutch, because it goes like an electric car with a binary switch.

This happens rarely, but when this controlling problem eats the engine power reserves in a bad moment, baking assist power is reduced somewhat so I need to push the brakes harder. This can be quite dangerous.

When the A/C rests or I turn it off, the problem goes away and the engine runs smoothly.

I'd appreciate any idea for a solution.

Thanks, James