Over the weekend my car started making a funny noise coming out of the exhaust and easily audible from inside the cabin, lots of little pops, think like 5 per second, pretty fast, not really loud either just like a burble it just hasnt done it before and it got me a little worried, I dont think its a bad thing, a bad batch of fuel was my first thought but it only started doing it when the tank was on about half (BP Ultimate) but it dosnt do it all the time, it was doing it everytime i came to a standstill at traffic lights for a few minutes but then it just went away and happened again a similar way the next day.
I have a PFC hand controller and there dosnt seem to be any problem there, Max knock rating was a very low 8,
water temp normal, revs normal, injectors never passed 30% duty
just wondering if anyone could shed some light.