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2006 F-150 4.6L V8 Misfire Codes 300, 302, 305 After Fuel Pump Replacement

Model: 2006 F150 Fault Code: P2177 Posted: 2012-05-16 12:31

I'm new to this forum, so please forgive any mistakes. I own a 2006 Ford F-150 Supercrew with a 4.6L V8 engine. A few weeks ago, I started noticing a significant fuel leak near the top of the fuel tank. After extensive research and visits to the dealership, I diagnosed it as a broken fuel feed nipple on the fuel module (fuel pump assembly). I replaced the entire pump and sending unit with an Alltex unit, along with new fuel line retaining clips and EPV retaining clips. The first start was smooth, and the truck ran well for 300 miles. However, after that, the idle became rough, and a 'Check Engine' light reappeared. My code reader displayed misfire codes: 300, 302, and 305 — indicating misfiring cylinders. The truck has 112,000 miles on it. I'm concerned whether this issue stems from the fuel system, EPV, or possibly faulty injectors. I recently replaced the fuel filter during the pump replacement. While I understand that ignition issues are less likely to appear suddenly after a fuel fix, I'm still unsure of the root cause. Could the problem be related to the fuel pump driver module? Or could it be a cam phaser issue causing timing misalignment? I've heard that rust in the fuel pump driver module (located near the spare tire carrier) is a common failure point on this model. I'd also like to rule out vacuum leaks, though I don't have direct access to the vacuum system. Thanks for any insights or suggestions.

Related fault codes

P2177

Comments (4)

Anonymous 2012-05-17 05:15

The fuel pump issue might not be directly related. On many 2006 F-150s with 4.6L V8 engines, low fuel pressure isn't usually caused by the pump itself but rather by corrosion in the fuel pump driver module located near the spare tire carrier. Even a minor rust spot on this module can cause misfires and erratic engine behavior. I'd strongly recommend inspecting that module — if it's corroded or damaged, replacing it could resolve the 300/302/305 codes. Additionally, cam phaser failure is another known issue on these trucks; when a cam phaser malfunctions, it can cause one bank of cylinders to misfire. This would typically show up as a single-side misfire. Make sure there are no vacuum leaks — they can also trigger similar symptoms.

Anonymous 2012-05-17 06:04

I agree — a proper diagnostic shop should check for vacuum system issues, especially on older F-150s with the 4.6L engine. The fuel pump driver module is known to corrode over time and can cause intermittent misfires that mimic fuel delivery problems. If this module has been exposed to moisture or road conditions, it may be a key culprit.

Anonymous 2012-05-17 19:53

You don't necessarily need a professional shop for diagnosis. With a basic OBD2 scanner capable of reading generic data streams — including fuel trim and engine load information — you can monitor real-time fuel delivery and misfire patterns. This helps determine whether the issue is fuel-related or ignition-based, without needing to disassemble components.

Anonymous 2012-05-18 09:41

I’ve done the tank drop myself to replace the pump, but I have limited experience with vacuum systems. The truck runs smoothly after a brief stutter on startup — it’s not rough under load or at highway speeds. Since the Check Engine light has gone off and previous fuel-related codes are no longer present, this suggests the issue may be mechanical rather than fuel delivery-based. Still, I’m open to suggestions about checking the driver module or cam phaser as potential root causes.