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1996 Ford Contour V6 2.5L P0174 Code: System Too Lean Bank 2 - Diagnosis and Fix

Model: 1996 Ford Contour Fault Code: P0174 Posted: 2009-03-27 21:56

I own a 1996 Ford Contour with a 2.5L V6 engine. After the check engine light came on, I received fault codes P0174 and P0171 indicating a lean condition in Bank 2. I performed a tune-up and cleared the codes, then drove it around the block. The check engine light returned with code P0174 — System Too Lean Bank 2. Any advice would be greatly appreciated. I've heard that cleaning the Mass Air Flow (MAF) sensor might help. Would this resolve the issue? Current readings: - STFT B1: 14.06% - LTFT B1: 21.88% - STFT B2: 17.97% - LTFT B2: 25.00% - Calc Load: 28.63% - Engine RPM: 717 - Fuel System: 1 CL - ECT (Coolant Temp): 75°F I'm looking for a reliable, cost-effective solution to fix this lean condition and prevent further code recurrence.

Related fault codes
P0174
Comments (6)
Anonymous 2009-03-28 07:48

Cleaning the MAF sensor with an electronic cleaner may help improve readings. However, it's equally important to check for vacuum leaks — especially in the PCV system and its hoses. There’s a common elbow located near the throttle body that tends to fail over time. While hard to access due to its position, inspecting this area can reveal potential issues. Good luck, and please update us on your progress.

Anonymous 2009-03-28 08:47

Given the current fuel trim values, a lean condition in Bank 2 is likely to eventually trigger P0171 as well. While cleaning the MAF sensor might offer some improvement, it's essential to first rule out vacuum leaks before assuming the issue lies solely with the sensor.

Anonymous 2009-03-28 10:27

Thanks for the tips! Can I perform a vacuum leak test using carburetor cleaner — or do I need a professional smoke test? I'm on a tight budget. I recently replaced the PCV valve, but it didn’t seat tightly when installed. How can I remove the factory clamp (it's a one-piece banded type) that’s difficult to access? Also, when I removed the old valve, I noticed the metal tube attached to the rubber elbow moved slightly — is this something I should be concerned about? I’ll update you if any of these steps help. Thanks again!

Anonymous 2009-03-29 18:58

Vacuum leaks are often found in that area. You can use carburetor cleaner for a basic test, but proceed with caution — apply it slowly and avoid spraying directly into the intake.

Anonymous 2009-03-30 11:24

I identified the leak: it was in the tube where the PCV valve sits, and in the ribbed plastic hose connecting the PCV valve to the filter housing on the firewall. The plastic joint had cracked at the tee connection point where it meets the rubber hose leading to the PCV valve. After cleaning the MAF sensor and repairing the vacuum leak, both codes have cleared. Thank you all for your help — I truly appreciate it!

Anonymous 2009-03-31 06:22

Great to hear you've resolved the issue! Your experience is valuable for others facing similar problems with older Ford Contour models.