The 1990 Volkswagen Passat has 3 recalls, the most serious involving a loose throttle component that can block the throttle plate and cause the engine to surge unexpectedly when the vehicle is put into gear.
A small tube inside the throttle housing can work loose and fall against the throttle plate, preventing it from returning to a normal idle. When this happens, the engine holds unexpectedly high RPMs in drive or reverse, making the vehicle harder to control from a stop. On the cooling side, if the engine overheats and continues to be driven in that condition, a heat exchanger inside the cabin can begin to leak hot coolant onto the driver's feet or release steam into the passenger compartment, which can cloud the windshield and reduce visibility. There is also a concern with certain vehicles equipped with heated front seats: the seat back heaters can concentrate heat in one spot or run hotter than the controls can manage short of turning them off entirely, creating a burn risk for anyone sitting against the affected area.