Found the problem that was causing the cylinder 5 misfire. A valve lash adjuster had fallen apart. This is located in the rocker arm. Battled this misfire for a month. Spark plugs, wires, injectors, fuel pump, mass air-flow sensor, had the ECM checked. Was still misfiring. Compression test was 250 psi. Was baffled. Upon starting the car, there would be no misfire. THEN SUDDENLY, it would start missing. Code was cylinder 5. Finally found this lash adjuster.
