if some parts / particles from your air filter element gets sucked into your throttle body / carburettor, there's only 1 thing you can do : stop driving the car, send / tow it to your mech as soon as possible, and open up the head. those filter elements should be somewhere between your piston and your block's head lah. shouldn't drop into your crank unless your rings are shot. about the grinding noise when putting car into gear, might be due to some probs at the gearbox's shaft. does your clutch pedal feels funny / different whenever you press it. if it does, then your clutch maybe got some gremlins lah.