For the most part, with that OBD system, various ignition components can fail without recording a fault code. The OBD is better for tracing down sensors out-of-range, etc.

Several people have reported that unmounting the ignition power stage and cleaning up the interfacing surfaces of the module and the fender cured their problem. A light coating of dielectric grease can help delay future oxidation. I'm nearly certain that neither a failure of the power stage or its grounding with throw a code - nor will a bad spark plug, plug wire, dist cap, rotor, coil....