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2003 Ford Escape 3.0L Engine Misfire: P0316 and P0304 Diagnosed with TSB 207584

Model: 2003 Ford Escape Fault Code: P0304 Posted: 2016-03-12 01:10

I recently replaced the coil-on-plug (COP) connectors on my 2003 Ford Escape V6 3.0L engine (OD: 268,000 miles). The original connectors were brittle and broke during removal, so I used spot plastic welding to secure them in place. After driving approximately 200 miles, the vehicle ran smoothly with good power but exhibited higher-than-usual fuel consumption. A visual inspection of the COP connectors revealed no issues. However, one intake manifold bolt became loose and eventually broke. After replacing it, I noticed a slightly rough idle initially, which improved after a few minutes. The next day, after parking for the night, the engine failed to idle properly upon restart. The OBD2 scan showed both P0316 (Random/Multiple Cylinder Misfire Detected at Start) and P0-than-usual fuel consumption. I found Ford Service Bulletin 207584, which addresses COP ignition system issues related to misfires or rough running. My question: Does this TSB apply directly to my situation? How should I troubleshoot the suspected misfire in Cylinder 4? The misfire appears to occur only at idle (50–55 mph) and disappears during highway driving, with a noticeable power loss afterward. Could the broken intake manifold bolt have allowed cold air into the engine, leading to valve damage or a misfire? Any advice on next steps—such as resetting the engine control module via OBD2 or removing the battery for a reset—is greatly appreciated.

Related fault codes
P0304P0316
Comments (2)
Anonymous 2016-03-12 09:17

Why did you replace the plugs? Was it routine maintenance or to address a specific issue? Start with new COP connectors and ensure springs are properly installed if needed. What brand and type of plugs did you use? This matters for compatibility with your 2003 Ford Escape V6 engine. You currently only have P0304 (Cylinder 4 misfire) and P0316 (misfire at start). Based on this, the loose intake manifold bolt issue is less likely to be the root cause—though you should check for vacuum leaks using the traditional spray can method. The TSB 207584 summary won't directly help here because the COP connector failure was already present before diagnostic testing. Do you have access to a Ford WDS (Workshop Diagnostic System)?

Anonymous 2016-03-14 21:27

Apologies for the delayed reply. The high mileage prompted me to replace the plugs as routine maintenance—I hoped it would resolve the ongoing issues. I used NGK plugs, which are common for this engine model—what is the recommended plug type specifically for a 2003 Ford Escape V6? There are no other diagnostic codes. I started with replacing the COP connector and spark plug in Cylinder 4, which temporarily resolved the issue. Now, should I reset the engine light via OBD2, or would removing the battery for a period (e.g., 15 minutes) be more effective? Will this allow the vehicle to relearn normal idle behavior and shift patterns?