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P0300 Fault on 2002 Isuzu Rodeo: Fuel Pressure & Coil Pack Issue Resolved

Model: 02 Isuzu Rodeo Fault Code: P0300 Posted: 2009-10-13 10:43

The P0300 misfire code on a 2002 Isuzu Rodeo is commonly linked to low fuel pressure, especially in vehicles with GM-sourced components. While I don't have the exact fuel pressure specification memorized, many models of this era show symptoms consistent with insufficient fuel pressure—this could explain the intermittent engine misfires. Could you confirm your vehicle's year and engine size? The original post mentions a 2002 model, which matches common configurations. For reference, the factory service manual (FSM) specifies that fuel pressure should start at 48–55 psi when the engine is cold and maintain a stable level during operation. Additionally, one user reported that fuel pump flow tests showed 400 mL in 15 seconds—within the FSM's recommended range. However, another noted that fuel pressure dropped from startup to running conditions by only 3–15 psi, which may indicate an issue with pressure regulation or delivery. The current diagnostic codes include P0131, P0134, P0138, and P0158—related to oxygen sensor performance. These suggest potential issues in the upstream sensors or fuel system consistency. A more advanced scanner is planned for further analysis. Another user reported a 2002 Isuzu Rodeo LS V6 with Delphi coil packs (part numbers 19005240). Each coil has a four-digit code on the side: 1D24, 1F08, and 1E19. The user has tried swapping coils between cylinders but still experiences a flashing check engine light above 2,000 RPM with P0300 intermittently appearing—sometimes even showing 'pass, no codes' on the reader after reinstallation. The issue persists even after reverting to original plugs (NGK GPower), indicating that the problem is not related to ignition components. The coil codes may hold diagnostic value; however, their exact meaning and mapping to specific cylinders are unclear.

Related fault codes
P0300
Comments (6)
Anonymous 2009-10-13 10:49

According to the factory service manual, fuel pressure should be between 48–55 psi at startup and maintain that level during operation. The current reading appears too low, which may contribute to misfires.

Anonymous 2009-10-13 13:38

My vehicle is a 2001 Isuzu Rodeo with a 3.2L engine. I checked the FSM and found it specifies a fuel pressure drop of 3–15 psi from startup to running conditions. My fuel pump flow test showed 400 mL in 15 seconds—within the recommended range. However, this doesn't rule out other issues like sensor faults or poor fuel delivery.

Anonymous 2009-10-13 15:17

So you're not concerned about low fuel pressure as a root cause?

Anonymous 2009-10-13 15:31

No, I'm not. After retesting the fuel pressure, it reached 40 psi—within acceptable range. I’ve ruled out fuel pressure as a primary factor.

Anonymous 2009-10-13 16:00

The current OBD2 codes are P0131, P0134, P0138, and P0158—indicating upstream oxygen sensor issues. I plan to use a more accurate scanner tomorrow for deeper diagnostics.

Anonymous 2010-05-17 13:43

I'm experiencing the same issue on my 2002 Isuzu Rodeo LS V6 with Delphi coil packs (part number 19005240). Each coil has a four-digit code: 1D24, 1F08, and 1E19. I've tried swapping them between cylinders, but the check engine light still flashes above 2,000 RPM, and P0300 appears intermittently—sometimes even showing 'pass, no codes' on the scanner. Anyone know what these four-digit codes mean or which one corresponds to cylinder #6? The problem started after installing NGK GPower plugs, but it persists when original plugs are reinstalled. Any insights would be greatly appreciated.