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P0303 & P0316 Diagnosis: 2005 Ford Taurus 3L DOHC V6 Durateck Misfire Fix Guide

Model: 2005 Ford Taurus 3L DOHC v6 Durateck Fault Code: P0303 Posted: 2010-03-06 18:18

I'm experiencing intermittent engine misfires and a flashing check engine light on my 2005 Ford Taurus with the 3.0L DOHC V6 Durateck engine. The fault codes detected are P0303 (Cylinder 3 Misfire Detected) and P0316 (Engine Misfire Detected During First 1000 Revolutions). The misfiring occurs intermittently, especially at low RPMs and during light acceleration—sometimes even while idling at a stoplight. The engine doesn't stall but feels like it's about to stutter. I've already changed all fluids, air filters, and used fuel injection cleaners multiple times without resolving the issue. I’ve noticed that easing off or increasing throttle flow can temporarily smooth out the misfire, but it doesn’t prevent it consistently—especially under cruise control. The engine starts reliably and never fails to start. My current troubleshooting steps include checking spark plugs, ignition wires, fuel pressure, vacuum leaks, and compression. I’m considering replacing cylinder 3’s spark plug and inspecting its coil pack, as misfires at low RPMs often point to weak or faulty ignition components. I’ve also read that P0316 is typically triggered by persistent misfires during startup—so resolving the root cause of cylinder 3 misfiring should clear both codes. Where should I prioritize my diagnostics? Are there known common failures in this engine model related to these specific codes?

Related fault codes

P0303P0316

Comments (10)

Anonymous 2010-03-07 08:33

Begin with a systematic check: inspect the ignition system (spark plugs, ignition wires), verify compression, test fuel injectors, and consider using a vacuum gauge to detect leaks. These are common sources of misfires in the 3L DOHC V6 engine.

Anonymous 2010-04-19 08:15

We performed all recommended checks—spark plugs, wires, compression—and everything appeared normal. Does that mean an ECU reflash is necessary? I'm not convinced it would resolve a severe misfire causing the check engine light to blink.

Anonymous 2010-04-19 10:50

An ECU flash will not fix a hard misfire that damages the catalytic converter. This is likely a bad valve or high-resistance ignition wire. Could you share details on how compression, spark plugs, and wiring were tested? That would help validate the diagnosis.

Anonymous 2011-04-08 22:45

To: toolchic and Joe, I’ve been experiencing P0303 and P0316 (cylinder 3 misfire) on my 2003 Ford Taurus 3.0L DOHC—same symptoms as you described. The engine misses at idle (~550 RPM) and under moderate acceleration, especially below 2000 RPM. It runs smoothly at higher speeds. I’ve checked the OBD-II codes via AutoZone’s dongle: P0303 indicates a misfire in cylinder 3; P0316 points to crankshaft position sensor signal errors. Probable causes: - Ignition system faults (spark plugs, wires, coil) - Vacuum leaks - Injector failure - Fuel pressure issues P0316 is often caused by persistent misfires during startup—common in this engine model. I’ve reviewed similar threads on OBD-Codes.com: https://www.obd-codes.com/forums/viewtopic.php?f=1&t=3257, https://www.obd-codes.com/forums/viewtopic.php?f=1&t=830. One resolved case pointed to plug corrosion. I suspect the issue is ignition-related—especially since misfires only occur at low RPMs and under load. I plan to start with checking spark gap on cylinder 3, then replace the plug. Next, locate and test the coil pack for cylinder 3 (known to have individual coils in this engine). If needed, swap or replace it. I’m hesitant to replace all six wires due to cost—currently in a budget mode. Any diagrams showing cylinder positions under the hood? That would help with visual identification.

Anonymous 2011-04-09 20:01

A year later, I suspect the car was either scrapped or sold to someone who fixed it. What repairs have you actually attempted before moving on?

Anonymous 2011-04-09 23:01

The misfire only occurs under low RPM and heavy engine load—such as when lugging the engine. When I shift into a lower gear (increasing RPM), the engine runs smoothly. Since it performs fine at high speeds, fuel or air delivery issues are less likely. This points to an ignition system problem. There are two main types of spark issues: weak spark (insufficient voltage to ignite the plug gap) and spark leakage (current leaking to ground instead of jumping across the gap). Weak spark could stem from high-resistance connections, oversized spark gaps, or a failing coil. Spark leakage would only make sense if spark strength peaks at low RPM—something I’m unsure about given modern ignition systems. For older magneto types, spark was strongest at high RPMs. To check for leakage, look for burn marks on the plug or wire, or observe stray sparks at night. If the issue is weak spark, I’ll start by verifying the gap on cylinder 3’s spark plug. Then replace it. Next, locate and test the coil pack for cylinder 3—this engine uses a separate coil per cylinder. After that, consider replacing wire #3 (though I’d prefer to avoid buying all six due to cost). Any diagrams showing cylinder layout under the hood? That would help with accurate identification.

Anonymous 2012-06-09 23:46

For reference on P0316: https://www.obd-codes.com/p0316

Anonymous 2012-07-07 15:32

I’ve had the same P0303 and P0316 codes on a 2003 Ford Sable DOHC. The engine misfires at idle and under light loads, always below 2000 RPM. Changed plugs and wires—no improvement. I assumed the coil was fine because the engine runs smoothly at high RPMs. Next, I checked the Crankshaft Position Sensor (CPS) and its wiring. It’s hard to access on this engine. I inspected the connector and confirmed it was secure by wiggling it. After starting the engine, the problem disappeared. This suggests a loose or corroded CPS connection. I’ll clean and secure the connector to prevent recurrence.

Anonymous 2012-08-09 18:53

Same issue on my vehicle: P0303 and P0316. Plugs and wires replaced—no fix. Turns out it was a faulty coil pack. Replacing it resolved the misfire completely.

Anonymous 2012-08-09 18:57

Same as above: I had P0303 and P0316 on my 2003 Sable DOHC with rough idle under light loads and below 2000 RPM. Plugs and wires replaced—no improvement. Assumed coil was fine due to smooth performance at high RPMs. Next, I checked the Crankshaft Position Sensor (CPS) and wiring. It’s difficult to access. I confirmed the connector was tight by wiggling it. After starting the engine, the problem vanished. This confirms a CPS connection issue. I’ll clean and secure the connector to prevent future problems.