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1998 Dodge Ram Van P0351 and P1391 Codes: Stalling, Misfiring, and Heat-Related Issues

Model: 98 Dodge Ram Van Fault Code: P0351 Posted: 2014-05-18 10:32

I'm completely stuck with my 1998 Dodge Ram Van 3.9L engine. The vehicle stalls while driving or at a stop, and I've recently noticed the ABS and check engine lights coming on. After purchasing a code reader, I found two persistent fault codes: P0351 (Ignition Coil A Circuit Malfunction) and P1391 (Intermittent Loss of Crankshaft Position (CKP) or Camshaft Position (CMP) Signal). I replaced the ignition coil (addressing P0351), then later fixed the ABS and speedometer issues by replacing the rear differential speed sensor. Following that, a P0339 code appeared—likely from the crankshaft position sensor—which I also replaced. Afterward, P1391 reappeared, so I replaced the distributor pick-up sensor (assuming it was faulty due to prior crank sensor replacement). I took the van for another test drive, but after just five minutes, symptoms worsened: severe stalling, rough idle, and engine bucking. I cleared all codes again and checked for timing slack by hand-cranking the engine—there was approximately 7 degrees of play in the distributor rotor. My question is: What could be causing these intermittent issues? Is it related to heat (since symptoms worsen when the engine warms up)? Could the ignition coil, PCM, or aftermarket sensors be at fault? I’ve cleared codes after every repair and still see recurring problems. Any insights would be greatly appreciated.

Related fault codes
P0351P1391
Comments (10)
Anonymous 2014-05-18 13:07

P1391 is likely due to an intermittent loss of CKP or CMP signal, especially related to sensor sync issues. This is a complex DIY fix that requires proper tools. A diagnostic scanner with live data can help verify if the signals are in sync—moving the distributor may temporarily restore alignment. For intermittent faults, an oscilloscope is ideal to detect missing or skipped pulses.

Anonymous 2014-05-20 07:38

I have a basic scanner that only reads codes and doesn't provide live data, so I can’t perform sync checks on my own. I’ve noticed the engine runs fine when cold but starts misbehaving as it warms up—could this be heat-related? Are the ignition coil or PCM components possibly failing under high temperatures?

Anonymous 2014-05-20 11:36

Ignition coils are a common suspect. However, the PCM is also a potential source of failure. I strongly recommend using OEM-quality sensors—aftermarket CMP and CKP sensors are known to cause intermittent faults. If you're seeing P1391, the camshaft or crankshaft position sensor should be verified for proper signal integrity. Fuel trims could also provide useful diagnostic data.

Anonymous 2014-05-24 12:30

My STFT is 18.8, LONGFT is 0.0, MAP reading is 11.2. Catalyst and oxygen sensor monitores are both increasing—though I’m not sure what this means. I’ll do further research to understand these values.

Anonymous 2014-05-24 13:04

Start with diagnosing P1391, focusing on signal sync issues. The STFT and MAP readings suggest a possible vacuum leak—this could be contributing to the misfire. Note that 'Catalyst mon was INC' and 'Oxygen ses mon was INC' are typically reset after code clearing and don’t reflect actual system health.

Anonymous 2014-05-27 15:01

I removed the crankshaft position sensor and found it rubbing against the flywheel. The mounting bracket wasn't perfectly perpendicular—so I added shims to correct alignment. After six local trips, the engine hasn’t stalled. On my last drive, there were a few instances of misfiring and spark knock. This is a significant improvement—I’m grateful for the advice. Any thoughts on what might be causing the spark knock or misfire?

Anonymous 2014-05-27 15:31

I’d still recommend verifying whether you’re using OEM sensors—aftermarket parts, especially for CMP and CKP, are known to cause problems. This is a common issue in older Dodge Ram models.

Anonymous 2014-05-27 19:37

Yes, I confirmed the crankshaft sensor is aftermarket. A close friend of mine also believes OEM sensors perform better and are more reliable. Given my experience with multiple repairs, I now agree with this view. Could the spark knock or misfire be related to the crankshaft sensor installation? Should I consider replacing it or look elsewhere?

Anonymous 2014-05-28 07:59

Once you’ve resolved known issues like sensor alignment and quality, retest the system and evaluate performance before moving on to further repairs.

Anonymous 2014-07-26 19:09

P0351 indicates a faulty ignition coil—though I replaced it over a year ago. Given our tropical climate with high heat, coil failure due to overheating is possible. Should I replace the distributor pickup coil? It’s located at the ignition module. I’m currently looking at AutoZone parts and see they offer a replacement pickup coil—should I go ahead with that?