Aug 28, 2019 · Some of the symptoms of a bad powertrain control module are 1) Illuminated check engine light The check engine light only turns on if the ECM (Engine control module) is analyzing the data it receives not up to standards. 2) Intermittent cylinder misfires Mar 19, 2004 · Question from Philippe (1957): I ask myself some questions about the ignition coil location: on all old Mopars the ignition coil sat atop the intake manifold; this location is not perhaps the best for the life of the coil: there's a lot of heat transferred to the coil and I have some friends who had ignition problems because the coil was (or became) bad. If the coil is faulty, you may have difficulty starting your car or it may not start at all. Misfiring, loss of power, poor acceleration. Once the car is running, a bad ignition coil can cause poor operation of the engine.