Changed coil pack, plugs, ignition module and problem remains. Removed coil pack and removed plugs...they each look the same, the "boots" and inner springs look clean as well as the plugs...the plugs each look the same...looked at the pins on the electrical connector to the ICM and there is no oxidation. It appears the ECM is not getting the confirmation signal that #2 cylinder is firing...What else do I consider except the ECM.
Engine light on indicating #2 cylinder misfiring:consider what is shared below. on 2005 Saturn Ion
by Visitor in Franklin, TN on August 13, 2011
ANSWER by mastertech6371 , August 13, 2011
check compression which is the first thing that should have been done before throwing all those parts at it. if it is ok, you need to have the injector checked and also look for any vacuum leaks. Roy