2002 Nissan Sentra 1.8 Engine Misfire and P0335 Crank Sensor Issue - Diagnosis and Repair Steps

A detailed case of a 2002 Nissan Sentra 1.8 experiencing persistent engine misfires and multiple diagnostic trouble codes (DTCs), including P0335 (Crankshaft Position Sensor A Circuit), P0303 (Misfire #3), P0350 (Ignition Coil Primary/Secondary Fault), and P0420 (Catalyst Efficiency Below Threshold). The vehicle was originally owned by the customer since new and had a recall-based crankshaft position sensor replacement during its first year. No issues were reported until recently. Initial symptoms included engine running on three cylinders with Check Engine Light (CEL) illuminated. A scan revealed P0303 and P0350. After swapping ignition coils, the misfire followed the coil — confirming a faulty coil. Replacing it with a new unit and clearing codes resulted in normal operation during a 30-minute road test. A week later, the customer reported the vehicle stalled while driving and failed to start until sitting for several minutes. Upon inspection, the engine ran well but still showed a persistent CEL. The scan revealed P0335 — indicating no crankshaft position signal during cranking. The wiring was inspected and replaced with a generic (jobber) sensor. After clearing codes, the vehicle ran normally for 30 minutes but failed to start after sitting. A repeat scan confirmed P0335. No RPM signal was detected when cranking. A dealer-grade crankshaft position sensor was then installed. The engine started and ran for one minute before stalling. Scanning revealed P0335 again. Replacing it with the jobber sensor allowed a 10-second run before failure, and now codes include: P0335 (Crank Sensor) P1102 (MAF Heater Circuit Fault) P0350 (Ignition Coil Primary/Secondary) P0420 (Catalyst Efficiency Below Threshold) After a thorough inspection of the wiring harness, grounds were cleaned, and a loose battery terminal was tightened. The vehicle restarted and ran for 15 minutes before stalling. Scanning showed no active codes. However, when attempting to start again, there is still no RPM reading during cranking — despite the absence of CEL illumination. This presents a puzzling contradiction: why would there be no RPM signal during cranking but no Check Engine Light? The issue appears to involve sensor reliability and potential ECM (Engine Control Module) incompatibility with certain sensors or wiring configurations, especially given that this model year is known for crankshaft sensor recall issues. Any insights into resolving the P0335 issue while maintaining proper cranking signal detection would be greatly appreciated.