This paper presents a process flow of an efficient method to diagnose, identify and optimize non-optimum gas lifted wells for a gas-lifted oil field. During normal day-to-day operations, a Petroleum Engineer's deliverables include well lifting performance analysis as well as optimization. Gas lifted wells are deemed optimized when the injection point is at the deepest mandrel possible and no multi-pointing scenario is occurring. However, the real-life well production can be unstable, corroborated by real-time data of flowing tubing-head pressure, casing head pressure and gas lift injection rate. The analysis of these real-time data can infer non-optimized lifting, where one of the symptoms is valve chatter. This in turn translates to well slugging and affects the whole production system. In a field with a large number of gas lifted wells, the diagnosis of these types of cases requires a substantial investment of time each month. By utilizing this workflow, the time spent for lifting diagnostics can be reduced, as well as contributing to time savings for other meaningful tasks, i.e. designing new gas lift system on non-optimized wells. The Gas Lift Diagnostic workflow, which is developed using pre-defined logic and the existing well model, eliminates the time-consuming manual task that slows down work and streamlines the processes to generate more value for the business and organization.