hello people, it’s about a volvo 850 2.5l gasoline with 20v build yearb 96 the following problem: in empty run the rotary zal fluctuates between 1300 and 500U almost goes off. the thing can hardly be driven if man wants to give gas nothing comes only when man the gas pedal completely penetrates for about 2-3 seconds then he comes back only again but also after that is quickly gone again. flammable candles only looked at looks really good even with a ignition center the sparks checked ignition cables distribution finger and cap petrol filter oil trap flame screen underpressure flaps clean throttle flap cleaned empty run regulator cleaned crankcases all hatches new air filter all was made and still the same. does anyone know the problem? next I would exchange the potentiometer of the throttle flap. thank you first in advance greeting dj