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You said you finished your 'swap "a while ago". How many tanks of fuel is that? The odds of repeatedly getting bad fuel aren't high unless you're buying from shady, old discount pumps somewhere. The torco will almost certainly end the pinging (provided you're sure that's what you're hearing) but you probably won't want the added hassle and expense of running that forever.

As hard as it can be to imagine that a tuner would turn a car out that pings, they can. It happened to me when my car was just mild bolt-ons. He was blaming it on fuel, but after trying fuel from the stations he recommended and the car still pinged on tip-in throttle, I knew it was his tune.

I've also bought bunk fuel two tanks in a row before. So that's possible too. And it was from different stations both times. Big, new, highly frequented stations. So even those can sell bunk from time to time. But I wouldn't say it's likely to happen over and over again unless the station's fuel holding tanks are marked and filled incorrectly. I've never heard of that, but I'm sure at some point in time it's happened. You may want to try different stations as well to eliminate that rare possibility.