Honda Accord cylinder pressure fluctuation

That sounds familiar. I had similar symptoms – elevated fuel consumption, diminished engine power, and the check engine light – with my 2012 Opel Insignia. It was related to faulty sensors causing incorrect readings, which affected cylinder performance. Have you looked at sensor malfunction?

I haven't examined the sensors specifically, focusing more on mechanical causes like head gasket integrity or piston ring wear. Which sensors were implicated in your Opel Insignia, and how did you arrive at that diagnosis?

The mass airflow sensor and oxygen sensors were the primary culprits. The diagnostic process involved a scan to identify aberrant readings from these sensors. I would strongly advise consulting a qualified mechanic to conduct thorough diagnostics. It might be a sensor issue, or something more serious such as internal damage. Did the problems suddenly appear, or was there a gradual decline in performance?

Sensors are often overlooked. I brought my vehicle to a trusted mechanic. The diagnostic scan did point to a faulty sensor that was replaced without further problems or costs! Thanks for your helpful suggestions!