I'm trying to fix some driveability issues on a 13 ford focus st. Its got a handful of unknown mods and so we're kinda guessing and doing the best we can.
Under light throttle and lower rpm's the car will stop accelerating cleanly and you can hear the exhaust note change and start oscillating. If your looking at the logger you can see the spark advance jump up and down roughly 30 degree spreads. This is the first DI ford ecoboost I've dealt with so I'm not sure if there's something I have overlooked.
Car has aftermarket cobb intake, upgraded map sensor, full exhaust, upgraded externally gated turbo, fmic, pipes, bov and whatever else I can't tell.
Any insight or help is much appreciated.