98 Jeep Grand Cherokee 4.0L Stalling, No Start, and DTC P0351 - Ignition Coil Issue on Distributor Engine?
Hello, I own a 1998 Jeep Grand Cherokee with the 4.0L engine and over 180,000 miles. Over the past week, the vehicle has started stalling while driving and occasionally backfiring. When it stalls, I could usually shift into neutral and restart successfully to continue my drive. The issue has become more frequent, and now the engine cranks but won't start on the first few attempts. On Christmas Eve, while driving on the highway, I lost all power—engine stayed running but would not exceed 1,000 RPM no matter how much I accelerated. It eventually returned to normal after a couple of minutes. Recently, I received a DTC P0351 code indicating an ignition coil failure. The vehicle now cranks but does not start. I'm confused because the P0351 code typically points to ignition coil issues, yet my engine has a distributor rather than individual spark plugs with coils. Initially, I suspected a failing fuel pump or a faulty crankshaft position sensor (CKP), especially after the check engine light came on. However, the presence of this specific code is puzzling. Could there be another underlying issue? Why would an ignition coil fault appear in a distributor-based engine? Are there any diagnostic steps I should take to confirm whether this is truly related to the ignition system or something else?
Are you using an OBD2 scanner or trying the key-on-off (KOEO) trick? For a 1998 Jeep Grand Cherokee with a distributor, check if there's 12V at either terminal of the ignition coil when the key is on. Also verify voltage at both terminals of the injectors. Ideally, use a fuel pressure gauge to measure fuel pressure—try the tip below. Check for spark at multiple spark plugs and at the coil-to-distributor connection—this might indicate issues with the distributor cap or rotor. As someone attempts to start the vehicle, spray carburetor or brake cleaner into the throttle body—did it fire or attempt to run on the spray? Regarding your question: 'Why would I have an ignition coil code on a distributor engine?' — ensure you're using a reliable OBD2 scanner or code reader. Even in distributor-equipped engines, there are ignition coils (often located near each spark plug), and P0351 typically indicates that the Powertrain Control Module (PCM) is not detecting 12V from the coil, which can lead to misfires or failure to start. This could point to a faulty coil, wiring issue, or sensor malfunction even in older distributor systems.