connectors one by one. Whichever one you pull that doesn't drop the engine speed is the bad cylinder. Then, check the ignition coil connector and injector connector for that cylinder for corrosion and clean it off with contact cleaner if there is any. You should also check the power transistor unit for corrosion (all 4 connectors of it). If you need help locating any of these parts, let me know. Good luck.
Bernie Authorized sales rep for... For more information, pricing, or to purchase a system, feel free to e-mail me: bhsiao@newssun.med.miami.edu or visit the website