The 1990 Mitsubishi Eclipse represents a significant entry in the compact sports coupe and convertible market, co-developed with Chrysler and sold under the Diamond-Star Motors banner. Known for its stylish design, affordable performance, and the availability of advanced features like All-Wheel Drive on the GS-X model, the Eclipse offered a compelling alternative to competitors such as the Honda Prelude and Toyota Celica. Its engineering quality and reliability, particularly with the robust 4G63 and 4G63T engines, have made it a sought-after vehicle for enthusiasts and those undertaking restoration projects. The 1990 model year marked the introduction of this generation, which also earned recognition, including a spot on Car and Driver's 10Best list for the GSX variant, underscoring its performance credentials.

This comprehensive service and repair manual, presented in English, is designed to assist owners, mechanics, and technicians in maintaining and repairing the 1990 Mitsubishi Eclipse across all trims and engine options. It covers a vast array of systems, including powertrain, chassis, and electrical components, detailing everything from routine scheduled maintenance, fluid changes, and filter replacements to complex engine overhauls, transmission rebuilds, and electrical system diagnostics. The manual also provides essential troubleshooting guides, special tool identification, and technical specifications, ensuring users have the knowledge required for effective vehicle care and repair, thereby helping to preserve the vehicle's value and performance.