I'm kind of leaning with the other guys suggesting you get a tune/diagnose the problem through the ECU. Having a professional take a deep look at exactly what's going on and pinpointing issues sounds way better than throwing parts/money at a problem that isn't fully understood. I wouldn't put too much faith into "some tune" from "some guy" when the engine is running poorly. It just needs checking, that way you know that end of things is good, and you don't have to assume that the tune is fine (because it very well may be not).
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