← Back to list

P0171 Fault Code on 1998 Plymouth Breeze: Causes and Solutions for Lean Mixture & Idle Issues

Model: Plymouth Breeze Fault Code: P0171 Posted: 2006-11-04 16:09

I'm experiencing an engine check light on my 1998 Plymouth Breeze with a 2.4L engine. The diagnostic trouble code (DTC) is P0171, indicating a lean air-fuel mixture. I've read online that a dirty Mass Air Flow (MAF) sensor is a common cause—however, I'm unsure whether my vehicle has a MAF sensor since I couldn't locate one. My car appears to be equipped with a Manifold Absolute Pressure (MAP) sensor instead, which controls air intake. A few weeks before the check engine light came on, I noticed the idle became unstable at stoplights—there would be brief stalling sensations that quickly recovered. This issue still occurs occasionally, especially during cold starts. Could this be due to a degraded oxygen sensor (O2), a Positive Crankcase Ventilation (PCV) valve, or even the MAP sensor? Neither of these sensors has been replaced yet, and my vehicle has 145,000 km on the odometer. Should I replace the PCV valve as part of maintenance? Additionally, I haven't had a fuel filter changed in years. Could low engine oil levels be contributing to this issue (even if indirectly)? Thanks for any insights.

Related fault codes

P0171

Comments (5)

Anonymous 2006-11-04 16:52

The most likely culprits are either the upstream oxygen sensor or an EGR valve that's stuck open. However, it's important to first check fundamental components such as fuel pressure, MAP sensor readings, coolant temperature sensor, and intake gasket integrity before moving on to more complex fixes.

Anonymous 2006-11-04 22:59

Does anyone know whether the 1998 Plymouth Breeze is equipped with a Mass Air Flow (MAF) sensor or relies solely on a Manifold Absolute Pressure (MAP) sensor? This distinction matters for diagnosing P0171.

Anonymous 2006-11-05 07:25

Yes, I've confirmed this—many vehicles like the 1998 Plymouth Breeze do not have both MAF and MAP sensors. They typically use one or the other, so it's important to verify which sensor is present in your model.

Anonymous 2006-11-15 00:01

Thanks for clarifying Jeff! I don't experience any driving performance issues—only intermittent idle hesitation, especially during cold starts. Sometimes, the vehicle feels like it’s shaking slightly (not severe). When I clear the P0171 code using a scanner, the check engine light usually returns after 20–30 miles and typically appears on the second cold start. Does this pattern suggest anything? The P0171 code is detected while driving within 10–15 minutes of starting, even when no check engine light is visible—then it triggers later. This behavior may indicate a transient sensor reading or a condition that worsens under specific conditions (like cold starts). Thanks for your help!

Anonymous 2006-11-15 09:31

While the MAP sensor could be involved, it's just one of many possible causes—many factors can lead to a lean mixture and P0171 code, so diagnosis should be systematic.