Are there any diagnostics experts on here? I have an 09 1.2 Fit/Jazz with 65000 miles on it that has been pinking/pinging since I got it two years ago. Below 2500 RPM it is impossible to give it any gas without a ton of rattling from the engine; as the revs go past this it picks up like a switch has been thrown. There is no fault code light on the dash, nothing to show that there is a problem, but of course there is! Would a garage with diagnostic equipment be able to discern any clue as to what the problem is? I'm sure that the problem is a weak mixture, but as there is no adjustment, then there is no cure. I know that the anti-knock sensor is working as the engine loses power as soon as I ask for any acceleration at low revs.

Or should I scrap the car and cut my loses?

 

Have someone to borescope combustion chambers for carbon deposits and check for overheating due to restricted exhaust

 

Is it likely that carbon could have built up at this mileage? I would have thought that any exhaust restrictions would be more of a problem at higher revs?