9000 slows down itself

Hello SAABiner! Here’s a strange problem that I’ve been observing for a long time: (vehicle is a 9000 B234 2.3 FPT hand switch) No matter what gear and what speed, the car seems to brake itself! And indeed, neither any brakes are fixed or rusty, but you really feel that the engine slows down very strongly… Sure, if you take the gas path and brake yourself, it’s really extreme… Especially if I switch on the air conditioning system while rolling out with the gear in place, you feel a clear jerk as it slows down. Can it be that the climate compressor is stuck? Can it be on DI or candles? Or even the throttle flap??? (because if the throttle flap is completely closed, the engine gets hardly any air, or? That’s why it also slows down, because the pistons moving downwards have to work against the underpressure and thus are quite slowed down) maybe you have an idea…