GMC Safari Misfires & Stalling Traced to Bad Cam Sensor

Had similar issues with a 2000 GMC Yukon. The check engine light kept flashing while experiencing rough starts and stalling. Initial diagnosis pointed to sensor failure, but it turned out the magnetic encoder wheel on the camshaft was damaged. The camshaft position sensor was reading incorrectly due to this damaged wheel, causing the engine control module to get incorrect timing data. This led to constant misfires and stalling issues. The repair involved replacing both the encoder wheel and camshaft sensor as a complete unit. This was a serious repair requiring partial engine disassembly since the encoder wheel is mounted directly on the camshaft. The symptoms exactly match what you describe, especially the rough idle and stalling. The engine would run particularly rough during cold starts and had trouble maintaining steady idle. Consider having a professional check the encoder wheel specifically, as sensor replacement alone might not resolve the issue if the wheel is damaged. The previous repair might have only addressed the sensor without identifying the root cause.

Thanks for sharing your experience. Dealing with the same symptoms right now and that encoder wheel issue makes a lot of sense given my rough starts and ignition timing problems. The flashing check engine light matches too. Before I take it in for sensor testing, would you mind sharing what the total repair cost was in your case? Also curious if youve had any similar engine misfire issues pop up since getting the camshaft position sensor and encoder wheel replaced?

Thanks for asking about the follow-up. Since having the encoder wheel and camshaft position sensor replaced, my engine has run perfectly with no misfires or rough starts. The repair cost totaled 695 Euro, which included both parts and labor since accessing the camshaft required significant engine work. The engine control module now receives accurate timing signals, and the ignition timing issues have completely disappeared. The flashing check engine light hasnt returned either. Getting both components replaced together was key, the camshaft sensor works in tandem with the encoder wheel to maintain proper engine timing. If your symptoms match what I described, investing in this repair should resolve your issues. Just make sure your mechanic checks both components, as replacing just the sensor alone might not fix the underlying problem if your encoder wheel is damaged like mine was.

Took my Safari to a trusted mechanic yesterday based on your advice about the encoder wheel. After running diagnostics, they confirmed the camshaft sensor and encoder wheel both needed replacement. The repair cost came to 720 Euro total, bit more than yours but worth every cent. The shop completed the work in one day and the difference is night and day. No more engine misfires, rough starts, or stalling issues. The check engine light finally stayed off and the idle is perfectly smooth now. They showed me the old encoder wheel which was definitely damaged, causing all those sensor failure readings. Glad I got both parts replaced instead of just trying another sensor swap. The engine control is working exactly as it should now. Really appreciate the detailed insight, saved me from more frustrated trips to different shops looking for answers.