The formation of K+···Cl- heavy-Rydberg ion-pair states through dissociative electron attachment in K(np)/CCl4 collisions is investigated. The product ion-pair states are detected directly by electric field-induced dissociation. A Monte Carlo collision code is used to analyze the results that models both the initial Rydberg electron attachment and the subsequent evolution of the ion pairs. The data and the calculations demonstrate the production of long-lived bound K+···Cl- heavy-Rydberg ion pairs. They also suggest that collinear collisions can generate heavy-Rydberg states of low angular momentum.