A Vauxhall Insignia 2.0-litre presented with an idle fluctuating between approximately 800 and 900 rpm. Live diagnostic data was recorded and the engine was monitored throughout the cleaning treatment.
The starting point
The fluctuating idle was recorded before treatment. That observation described how the vehicle behaved; it did not by itself diagnose carbon as the cause or rule out a mechanical, electrical or control-system fault.
What was observed during treatment
After approximately 20 minutes, the engine was observed to have become quieter. At around 40 minutes, it sounded more responsive. These were workshop observations made during this individual treatment, not measured horsepower or economy results.
The checks after treatment
Post-treatment checks were completed. No specific MPG increase, emissions reduction, power gain or mechanical repair outcome is claimed for this case because none was measured and retained in the verified record.
What the case does not prove
One treatment cannot demonstrate that carbon cleaning cures every rough idle or restores a fixed amount of performance. Cleaning cannot repair a broken, worn or failing component.
When cleaning belongs in the process
Carbon cleaning is credible only when the vehicle is suitable and expectations are controlled. Visual checks, diagnostic checks, monitoring, a test drive where appropriate and final checks matter more than miracle language.
The lesson
Report what changed, preserve what was actually measured and be honest about what remains unknown. A useful observation is evidence; it is not permission to promise a cure.
QUESTIONS THIS CASE ANSWERS
Questions this case helps answer
Can carbon cleaning repair a faulty engine component?
No. Cleaning may remove deposits where the process is suitable, but it cannot repair a broken, worn or failing mechanical or electrical component.
Does a quieter engine prove that carbon caused the original problem?
No. In this case the engine was observed to become quieter during treatment, but that observation alone does not prove the original cause or establish a mechanical repair.
Does this Insignia case prove an MPG, emissions or power increase?
No. No verified MPG, emissions or horsepower measurement is claimed for this case. The page records only the observations that were retained.