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1996 Dodge Intrepid 3.3L V6: P0171, P0300, and P0301 Misfire & Emissions Failure - How to Fix?

Model: 1996 Intrepid Fault Code: P0171 Posted: 2006-09-01 08:42

I recently completed a tune-up and replaced the catalytic converter on my 1996 Dodge Intrepid with a 3.3L V6 engine. The vehicle now shows three diagnostic trouble codes: - P0171: System Too Lean (Bank 1) - P0300: Random/Multiple Cylinder Misfire Detected - P0301: Cylinder #1 Misfire Detected This issue is preventing the car from passing emissions inspection. I've already done a tune-up about 6–8 months ago, and the engine has accumulated approximately 106,000 miles. I'm seeking advice on what components to inspect or replace next—such as fuel pressure, ignition coils, spark plugs (platinum type), compression, vacuum leaks, or EGR valve function. The misfire has intermittently stopped, but the check engine light remains on and new codes have appeared, including P0401 and P0171. I’ve replaced the purge solenoid, which temporarily resolved the misfire—but after resetting the system, the code P0171 returned. I suspect a deeper issue with oxygen sensor feedback or EGR valve operation. Any guidance on diagnosing these codes using OBD-II tools would be greatly appreciated.

Related fault codes

P0171P0300P0301

Comments (10)

Anonymous 2006-09-01 10:32

P0171 is more commonly associated with the 3.5L engine in Intrepids, not the 3.3L. Could you confirm your vehicle's exact engine specification? I believe it's a 3.3L V6 MPI as per your VIN details.

Anonymous 2006-09-01 11:07

Yes, confirmed: 1996 Dodge Intrepid, 4-door sedan, 3.3L V6 MPI engine (as listed in my VIN). Tune-up completed about 6–8 months ago. Current mileage is approximately 106,000 miles. Thank you for the clarification.

Anonymous 2006-09-01 11:58

How many miles have passed since your last tune-up? What's the total engine mileage? Have a compression test and check fuel pressure—these are key indicators of misfire or lean conditions. Also, verify the spark plug and ignition coil brand used during the tune-up. How severe is the misfiring? Don’t forget to inspect the EGR valve for sticking. I’d recommend temporarily disconnecting the EGR vacuum line and testing performance afterward. Good luck—please update your progress.

Anonymous 2006-09-01 14:27

Today, the misfire stopped. The check engine light remains on, but new codes appeared: - Code 31: Purge solenoid circuit fault - Code 43: Ignition coil control circuit fault - Code 51: Oxygen feedback system stuck at lean position. Can you explain what these codes mean in terms of OBD-II diagnostics? Any insight would be helpful.

Anonymous 2006-09-01 14:30

Platinum spark plugs, Taylor resistor wires. Approximately 4,000 miles since last tune-up. Total engine mileage: ~106,000 miles. Thank you for the input.

Anonymous 2006-09-01 15:10

Are you seeing these codes during a key cycle (flashing check engine light)? The issue might stem from faulty oxygen sensors causing the PCM to interpret the air-fuel mixture as lean, even when it's not. Alternatively, an EGR valve stuck open could be creating a lean condition. Try removing the vacuum line from the EGR and plugging both ends—then drive the vehicle. This should generate an EGR-related code (likely P0401 in OBD-II). A compression test is still recommended, but if you don’t have access to a scanner yet, prioritize this step. I’m skeptical about using platinum plugs on a 1996 Intrepid—original equipment likely used standard iridium or copper-based plugs. Check for vacuum leaks around the intake manifold and hoses. The purge solenoid issue is unlikely to resolve misfiring; it may only mask symptoms. A proper OBD-I scanner would help confirm root causes. Please keep me posted.

Anonymous 2006-09-11 21:34

I replaced the purge solenoid, and the misfire stopped temporarily. After resetting the check engine light via battery disconnection, it returned with only Code 51: Oxygen feedback system stuck at lean position. Any ideas on how to resolve this?

Anonymous 2006-09-12 06:25

I’ve never seen a purge solenoid fix a misfire—this seems unlikely. The misfire monitor may still log a misfire even after the issue resolves. At this point, I strongly recommend using an OBD-II scanner to read accurate codes. Code 51 points to an oxygen sensor problem—specifically, one of the downstream sensors is likely malfunctioning or has faulty wiring. More details (e.g., which sensor) would help narrow down the diagnosis.

Anonymous 2007-06-28 12:10

Hello—I have a 1996 Intrepid with a check engine light and a mechanic says the O2 sensor is functioning correctly but showing zero volts to the PCM. He suspects either wiring or a faulty PCM. Any thoughts on this? Could it be a sensor issue or a signal reading problem?

Anonymous 2007-06-28 12:55

If your scan tool shows zero volts from the O2 sensor, that’s highly unlikely—O2 sensors typically produce voltage signals between 0 and 1 volt. A reading of zero suggests either a wiring fault, poor ground connection, or a faulty sensor. However, it's more probable that there is an issue with signal transmission rather than a PCM failure.