Dodge Caravan 1999 3.3L V6 P0353 Misfire After Replacing Ignition Coil - Intermittent Rough Idle and Code Recurrence
I own a 1999 Dodge Caravan SE with a 3.3L V6 engine, currently at 125,000 miles. The Check Engine light has been on intermittently since last year, showing code P0353 (Cylinder 3 misfire). Initially, the issue would resolve itself after a few days or driving periods, but recently the intervals between occurrences have shortened. After replacing the ignition coil, the problem persisted for about one week. The Check Engine light returned with the same symptoms: rough idle, especially after warm-up, and engine stalling during highway driving. When I restarted the vehicle, the rough idle would appear briefly—lasting less than a minute—and then the engine would smooth out. If I let it idle longer than that, it would recover. The issue only occurs after a warm start; it never appears when starting cold. Once the symptom resolves, there is typically a gap of several hours to a day before it returns. The rough running sometimes manifests while driving on highways, and if I allow the engine to stabilize, it recovers within one minute. On one occasion, attempting to accelerate caused the Check Engine light to flash—scan results showed multiple misfire events with a primary fault indicating Coil C failure (though the code was not captured at that time). I have inspected the wiring harness between the ignition coil and Powertrain Control Module (PCM), and found no visible damage. Resistance measurements from the coil terminals (A, B, C) to the PCM connector show 0 ohms for all connections and infinite resistance to ground—indicating a likely intact circuit. After replacing the spark plugs (Champion brand), I drove approximately 10 minutes, stopped at a grocery store, and upon restarting, the rough idle returned along with P0353. This suggests that the issue is not solely related to spark plug wear or gap. Given that the problem only occurs after warm-up and resolves after stabilization, I am considering whether the root cause lies in the ignition coil, wiring harness, or PCM itself. Since the symptoms are intermittent and have persisted despite replacing the coil and plugs, should I consider replacing the PCM next? What diagnostic steps can help isolate between these components? Any suggestions or testing procedures would be greatly appreciated.
A quick assessment: Was this a new ignition coil? If so, was it an OEM (Chrysler) unit from the dealer or aftermarket like Advanced Auto Parts? Check terminal #3 on the coil connector—could be loose or damaged. Replacement connectors are available. Unlikely but worth checking: Spark plug condition and brand. Did symptoms appear before the coil replacement? Terminal #3 is located at the rear center position of the spark plug assembly—the secondary wire refers to the spark plug wire connecting that cylinder to the ignition coil. I suspect a wiring or coil pairing issue—specifically, the 3rd and 6th cylinders may have swapped secondary wiring. The most likely culprits are the ignition coil, wiring between the PCM and coil, or the PCM itself. I strongly advise against immediately replacing the PCM without further diagnostics. More details to follow if time permits.