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1996 Dodge Ram 1500 5.2L Engine PO171 Code: Diagnosis and O2 Sensor Voltage Guide

Model: 1996 dodge truck 5.2l Fault Code: P0171 Posted: 2007-01-02 20:18

I'm experiencing a recurring PO171 code on my 1996 Dodge Ram 1500 with the 5.2L V8 engine. The code clears quickly after resetting, suggesting an intermittent issue. I've identified a small exhaust leak at cylinder #1 on the driver's side, but I'm unsure if this is directly causing the code or if there are other underlying problems. I'd like to know the proper voltage readings for both pre-cat and post-cat oxygen sensors during normal engine operation. All vacuum lines have been checked and appear intact. Could a problem with the intake system—such as a faulty throttle body or plenum—be contributing? I've used a brake cleaner-based diagnostic tool, but it hasn't improved RPM stability. What are the most likely causes of this code in this specific vehicle model?

Related fault codes
P0171
Comments (4)
Anonymous 2007-01-02 20:50

Air leaks in the intake manifold, exhaust pipes, or exhaust manifold can trigger a PO171 code. Your identified leak at cylinder #1 strongly suggests it's a primary cause of the check engine light. I recommend repairing the exhaust leak first, then clearing the code and monitoring whether it returns. This is often the most effective starting point for resolving this issue.

Anonymous 2007-01-03 09:21

On a Dakota (or Ram) with a cracked intake manifold or broken exhaust bolt, such leaks can cause similar symptoms. Be sure to inspect both the intake gasket and plenum pan for any signs of leakage as well.

Anonymous 2007-01-04 19:59

I'll start by fixing the exhaust leak at cylinder #1 and see if that resolves the PO171 code. Since the engine requires a near-perfect air-tight seal to run properly, this seems like a logical first step. Thanks for the advice—especially from carguy! I'm using a 1996 Ram 1500 with no broken bolts, but I'll replace them along with new intake gaskets as a precaution.

Anonymous 2007-01-05 11:00

That's a solid troubleshooting approach—fixing the leak first before moving on to more complex repairs.