The objective of this study was to investigate the effects of three methods of teaching diagnostic problem-solving (troubleshooting) to automotive students. The sample consisted of 45 community college students enrolled in automotive courses. Initially, all students received a presentation on ignition principles, and the Otis Mental Ability Test was administered to establish a covariate. Individuals were then assigned to treatment groups in equipment oriented instruction, textbook oriented instruction, or programed instruction. Following the treatments each student completed an attitude inventory, knowledge test, and a troubleshooting performance test. Analysis of covariance solutions indicated no significant differences existed in troubleshooting knowledge or attitude toward instruction. The equipment oriented treatment group required the shortest instructional time and its troubleshooting performance was significantly (.01 level) better than the other two groups. It was concluded that programed or text oriented methods were most effective for knowledge learning and equipment oriented methods were most effective for performance learning. Sample instructional materials and the instruments are appended. (EM)