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P0301 Engine Misfire: Diagnosis and Fixes for 2006 Jeep Commander 4.7L

Model: unknown Fault Code: P0301 Posted: 2020-04-15 11:41

I recently replaced all spark plugs, coil pack, and fuel injector for cylinder #1 on my 2006 Jeep Commander 4.7L. Despite these replacements, the engine still exhibits a misfire and fails to reach 50 mph. Using an OBD2 scanner, I've detected multiple fault codes: P2302 (Coil A secondary circuit), P2320 (Coil E secondary circuit), and another P2320 (Coil G secondary circuit). The engine runs but loses power and begins to cut out at higher RPMs. I'm concerned whether the coil wiring is correctly matched to the firing order—such as Coil A for cylinder #1, Coil E for cylinder #6—and if any underlying issues like oil contamination or mechanical damage are contributing to this problem.

Related fault codes
P0301
Comments (5)
Anonymous 2020-04-16 06:28

Check for exhaust or catalytic converter blockage—restricted flow can cause misfires and poor performance, especially in older vehicles with high-mileage engines.

Anonymous 2020-04-16 08:42

Thanks for the helpful tip. I'll check the exhaust system next.

Anonymous 2020-04-18 19:58

I've confirmed the firing order on my 2006 Jeep Commander 4.7L: Coil A corresponds to cylinder #1, Coil E to cylinder #6, and Coil G to cylinder #9. The engine runs but lacks power and starts to cut out at higher RPMs. I suspect a misalignment or failure in one of the coil packs, especially given that multiple secondary circuit codes are present. I'm also considering whether the coils are properly installed according to the correct firing order.

Anonymous 2020-04-18 21:28

Worn spark plugs can lead to coil pack failure. Ensure all spark plugs are in good condition and correctly seated. Verify if you're using a two-wire coil (common on older models). A digital multimeter (DMM) and test light are essential for checking circuit continuity. Confirm whether the P2302 and P2320 codes appear together—this may indicate a shared ground or wiring issue. After clearing the codes, monitor what new faults return and report back.

Anonymous 2020-04-19 08:17

Thanks for the insight. The root cause was actually low engine oil—my grandson drove the vehicle with extremely low oil levels, resulting in smoke and a sharp metallic knocking sound. After returning home, my son-in-law and grandson changed the oil, filter, and plugs, but symptoms persisted. I towed it to my garage, inspected the spark plugs, and found one was significantly worn compared to the others. I’ve replaced all plugs today and will monitor performance closely in the coming days.