1999 Pontiac Montana P0327 Code: Knock Sensor Issue Still Persisting After Replacement

What troubleshooting steps have you tried after replacing the knock sensor?

AutoZone specializes in selling parts, not diagnosing issues. Was the replacement knock sensor from a dealer or an aftermarket brand? Check the sensor's resistance using a multimeter. Inspect wiring for damage. Verify if the sensor is receiving 5V power and check both ground and signal connections.

The old knock sensor was completely broken—luckily, the plug didn’t come loose. I’ve inspected all wires and found no fraying. I’m unsure how to test for proper grounding or a signal from the sensor. Also, I don’t know how to verify if it’s receiving 5V power. Can someone guide me through these tests? I should clarify that I am a woman, which may be part of my experience gap in automotive repairs.

Did you clear the P0327 code using an OBD2 scanner after installing the new sensor? Or are you waiting for it to self-clear? Tips: Avoid applying sealant on the sensor threads—ensure proper sealing is used. Does your engine produce a ticking or knocking sound? Check for exhaust leaks. Have there been any prior repairs or maintenance work done before this code appeared? Note that P0327 may not directly cause stalling—it could be a symptom of an underlying issue like low fuel pressure, overheating, or other problems.

I did not apply any sealant during installation. The engine does not produce ticking or knocking sounds. There have been no prior repairs or maintenance issues. I suspect an exhaust leak—though I’m not certain. I didn’t clear the code initially, hoping it would self-clear. Should I have cleared it? The vehicle continues to stutter and stall, almost as if it’s running out of fuel. I'm now considering fuel pressure regulator, fuel pump, or fuel filter issues.

Re-read the codes—copy all stored trouble codes before clearing them. Then clear the code and monitor for recurrence. A knock sensor fault (P0327) typically affects timing adjustments but is unlikely to cause stalling on its own. However, engine knocking due to low fuel, overheating, or other conditions could trigger this code—but in such cases, additional codes should be present.

I re-read the codes and found only P0327. I cleared it, then drove for a block—stalling continued exactly as before. The same P0327 code returned immediately. I’m now frustrated and considering taking the vehicle to a mechanic. With only this one code present, what else should I check? Are there any other potential causes I haven’t considered?

Start with basic diagnostics: use a fuel pressure gauge, perform a leak-down test, and verify all spark plugs are firing properly. Check plug condition—wet, black, dry, or tan? Look for signs of damage. Test for vacuum leaks using the carb cleaner spray method: apply it to suspected areas; any change in engine sound or RPM may indicate a leak.

I’m not sure how to properly read spark plug conditions. The check engine light appeared after I ignored poor running performance, which started before the CEL came on. I’ve asked a friend who is more experienced in vehicles to inspect it soon. I hope they can provide a diagnosis or at least useful insights. Thank you all for your patience and support—I appreciate the help so far! I’ll update with any new findings.

Basic diagnostics are key: measure fuel pressure using a gauge, perform a leak-down test to check injector function, inspect spark plug condition (wet/dry/black/tan), and look for vacuum leaks. A simple method is to spray carb cleaner on suspected vacuum lines—any noticeable change in engine sound or RPM may indicate a leak.