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Dodge Ram 1500 Code P1391: Rough Running Engine Diagnosis & Fixes

Model: dodge ram Fault Code: P1391 Posted: 2006-11-19 12:15

My 1999 Dodge Ram 1500 with a 5.2L V8 engine is running rough and the issue has been getting progressively worse. I've already replaced the spark plugs, distributor cap, rotor, and ignition wires, but the problem persists—sometimes it runs fine, other times it sputters severely. The vehicle occasionally stalls when shifting into gear, and it doesn't move at all under load. I'm now concerned about potential sensor or fuel system issues. The engine has 118,000 miles on it, and I've used Autolite spark plugs with a gap of 45 degrees. I recently replaced the catalytic converter due to performance issues, but that may have contributed to current symptoms. I'm seeing Diagnostic Trouble Code P1391 (Crankshaft Position Sensor Circuit Malfunction) and want to know if this is related to the engine's rough idle or stalling behavior. Any insights on proper diagnostics or component replacements would be greatly appreciated.

Related fault codes
P1391
Comments (7)
Anonymous 2006-11-19 12:27

What year, mileage, and brand of parts were used during previous repairs? This helps narrow down potential causes.

Anonymous 2006-11-19 17:27

It's a 1999 Dodge Ram 1500 with 118,000 miles. I used Autolite spark plugs and Autolite ignition wires. It has a 5-speed manual transmission.

Anonymous 2006-11-19 17:28

I gap the spark plugs at 45 degrees as per manufacturer specs for this engine model.

Anonymous 2006-11-20 09:08

The coil pack is a common failure point—especially in older Dodge Rams. If replacing it doesn't resolve the issue, consider performing a full tune-up using genuine Mopar parts. Avoid Bosch spark plugs and wires—they perform poorly in Dodge engines and can worsen symptoms.

Anonymous 2006-11-20 10:57

The coil pack has already been replaced. I'm now considering switching to new cables and plugs. Could a faulty crankshaft position sensor be the root cause? Does it need replacement?

Anonymous 2006-11-20 11:13

Code P1391 can stem from multiple sources including the distributor assembly, wiring harnesses, or sensor faults—diagnostic testing is essential to pinpoint the exact issue.

Anonymous 2006-11-20 18:17

The truck won't move when placed in gear and starts to die. This has happened before for short periods during operation. I replaced the catalytic converter due to poor performance, and the oil was slightly low at the time. Could this be related? Any additional suggestions or diagnostics would be helpful.