Hey, all. Hoping you can help shine some light on a similar issue I am having.
I found some VP Octanium octane booster at a local Canadian Tire and decided to give it a try. Reason being, I am about to do a DSG tune and wanted to compare TCU maps (stock vs. TVS) with some octane booster in the car to rule out any knock or timing pull in the CVT-like feeling of the stock 7-speed software. Though slightly better with octane booster in low-RPM range, the factory DQ381 software still sucks.
Where things get interesting is after running a few tanks with octane booster and then switching back to straight premium fuel, I noticed what sounds like a knock or fuel ping in the 2-3k rpm range at higher loads.
My guess - which is purely a guess - is that a few tanks of what would be 102 octane was enough for the ECU to adapt timing / boost and now the car has what sounds like LSPI.
Mileage is 95,000 kms and the car has been well-maintained and never tuned. My only other guess is that any crap that’s come out of the injectors is causing it.
It’s strange to think it’s just coincidence because the car ran completely fine until I used the VP Octanium — and to be clear, it was not the ‘Unleaded’ version that’s advertised as safe with catalytic converters and O2 sensors. Unfortunately, I did not know about this one until after I ran the ‘off-road racing’ blend.
Hoping someone out there can help with a possible solution. Plugs are new, coil packs are new, fresh oil, and still the same issue. VW did a live scan and no knock (apparently) but it did register some misfires. Same knocking / pinging noise described throughout this thread. Super frustrating. Car has good compression straight across the board and pulls hard up top, it’s just at low-rpm under high-load that I am hearing the noise.
I am wondering whether there are fuel trims or anything in the ECU that can be reset to factory. Any help is much appreciated.