P0351 Fault Diagnosis: 2003 Dodge Ram 1500 SLT 4.7L Engine - Coil Circuit Issue or Timing Chain Problem?

P0351 is not a misfire code—please confirm the vehicle year and model for accuracy. This helps ensure proper diagnosis.

The original post didn't specify the year or model. It's a 2003 Dodge Ram 1500 with a 4.7L engine. Is the reported code P0301 (cylinder one misfire) accurate? Or is it actually P0351 as stated in the original post?

I am working on a 2003 Dodge Ram 1500 SLT with a 4.7L engine. The P0351 code appears when I cycle the ignition three times or connect an OBD-II scanner. This is not a P0135 code—my truck only shows P0351, though it does exhibit driveability issues.

I only see one code: P0351. No other codes are present during diagnostics.

The P0351 code indicates a primary/secondary circuit fault in cylinder one. Given the engine has over 209,000 miles, could a stretched timing chain be causing misfiring? Timing chain stretch can lead to inconsistent valve timing and ignition events—could this explain the issue?

P0135 refers to the oxygen sensor heater circuit (bank 1, sensor 1), not related to P0351. This code does not cause misfiring or driveability problems. Are there any noticeable performance issues such as rough idling or poor fuel economy?

When the check engine light comes on, the truck runs roughly and lacks power. It fails to shift into passing gear and cannot exceed 40 mph—shaking severely. With over 209,000 miles, I suspect a stretched timing chain. A mechanic recently mentioned this issue in another high-mileage case (over 249,000 miles). Could this be the cause?

While possible, timing chain issues typically affect engine performance regardless of whether the check light is on. A misfire due to P0351 would not be caused by a stretched chain alone. If it were an oxygen sensor heater issue (P0135), the engine might run rich or lean depending on temperature and would perform better when cold. Testing bank 1, sensor 1 O2 sensor function is recommended. Do you have access to a voltmeter or scan tool for diagnostics?

Are you using an OBD-II scanner capable of reading all diagnostic codes, including P0351 and related cylinder-specific faults?

I apologize—correct code is P0351, not P0315. I mistakenly referenced the wrong code earlier. The issue is indeed P0351, indicating a problem with the ignition circuit in cylinder one.

Have you tested for continuity and voltage on the control wire between the PCM and coil pack #1? A lack of pulse or open/short circuits could indicate faulty wiring or a failing coil.

Yes, I’ve tested the fuel injector circuit with a dim light (Patrick Colts) on cylinder one. The only other possibility suggested is timing chain stretch—what do you think about that?

What is 'Patrick Colts'? P0351 specifically relates to the ignition coil circuit for cylinder one. The PCM may shut down fuel injection to protect the catalytic converter. Use a noid light to verify signal from the PCM to coil #1. Confirm power feed to coil #1 and check for shorts or opens in wiring between coil and PCM. Timing chain issues typically cause broader performance problems, not isolated P0351 codes. Did this issue appear before the check engine light came on? If it were a timing chain problem, the truck would run poorly regardless of whether the light was on.

I'll verify with a noid light again. No—this misfire issue started only when the check engine light came on. Thank you for your detailed input.