2002 Chevrolet Avalanche 1500 5.3L: P0332 Knock Sensor Issue, Oil Pressure Spike, and Multiple Misfire Symptoms
I recently purchased a 2002 Chevrolet Avalanche 1500 with a 5.3L V8 engine and have been experiencing several concerning issues over the past few weeks. The truck has otherwise run well for about four months, but now I'm seeing recurring check engine light (CEL) activation and performance problems. The CEL first appeared about a week after I bought the truck and initially went off on its own. However, it reappeared during heavy rainstorms—staying on for one to two days before going away again. After a recent car wash, the light came back immediately and remained on. During this time, I noticed a slight knocking sound when starting the engine in the morning, lasting only 15–20 seconds. While driving on the interstate, I also observed reduced power—just barely noticeable—but it was concerning enough to check gauges. My oil pressure gauge read between 85–90 psi at 70 mph (normally around 55–60 psi), which alarmed me significantly. I pulled over and visited Advanced Auto to get the codes scanned. The diagnostic results showed three key fault codes: - P0300: Random/Multiple Cylinder Misfire Detected - P0332: Engine Knock Sensor Circuit (Bank 2) – Low Input Signal - P0650: Malfunction Indicator Lamp (MIL) Control Malfunction I’ve researched the P0332 code and found it’s a known issue on this engine model, often caused by water ingress into the knock sensor—especially after rain or washing. I’m wondering if a faulty knock sensor could be causing the random misfires indicated by P0300. Would replacing spark plugs and wires resolve the misfire symptoms? Or is there a deeper underlying cause? Additionally, why did my oil pressure spike so high during normal driving conditions? What should the typical oil pressure be at 70 mph for this engine? I’ve also noticed a noticeable vibration when idling or stopped—does that point to a tune-up or misfire issue? I’m considering an oil change due to the CEL blinking during my scheduled service. While I did get new oil and filter, I’d like to understand whether these symptoms are related and what steps I should take next. What is P0650? Should I be concerned about it? Are there known solutions or TSBs (Technical Service Bulletins) for the knock sensor issue on this model year? Is this a common problem among 2002 Avalanche owners? I’m not looking to replace parts blindly—I want to understand the root causes and ensure my truck doesn’t fail prematurely. Any real-world experiences, troubleshooting steps, or recommendations would be greatly appreciated. Thanks in advance for any insights!
As a precaution, check your engine oil for signs of fuel contamination. Use a mechanical oil pressure gauge to verify readings—many oil pressure senders tend to give false high readings. Perform a fuel pressure test and then conduct a KOEO (Key On, Engine Off) observation to monitor any drop in pressure. For the knock sensor (P0332), there is an official TSB from GM recommending replacement of both sensors and their connectors if water ingress is suspected. Always use original GM Delco parts—aftermarket components may not meet specifications. Spark plugs should be AC Delco brand for optimal performance. Hold off on addressing P0650 until you’ve confirmed oil, fuel, and mechanical integrity issues. Once these are ruled out, evaluate the TSB recommendations and sensor replacement as next steps.