Service function guideLoss of Power Diagnosis

This guide provides a complete diagnostic procedure for identifying the root cause of a loss of power complaint, covering the air, fuel, ignition and electronic control systems that govern engine output. It is written for working mechanics and experienced DIY owners who already understand basic engine operation and have access to scan tool data. You will learn how to prepare the vehicle and yourself, perform a logical step by step test sequence from easy checks to deeper diagnostics, and interpret the results to confirm a repair. After finishing the procedure you will be able to distinguish mechanical, electrical and calibration faults that cause a car to feel slow, and you will know how to verify the fix with a road test and live data.