1.8 LUW Cruze/Sonic Flex Fuel Surging

With a flex fuel sensor installed and enabled, a 2014 1.8L Cruze LS experiences severe surging, idle and coastdown instabilities while operating on fuel with an ethanol concentration greater than 50%, becoming more severe the greater the ethanol percentage. Car operates normally when the flex fuel sensor is disabled and the corresponding tables manually adjusted to the reported percentage.

This was fixed by copying/pasting the Torque Model coefficients from a 2015 1.8L Chevrolet Trax, with only minor adjustments required afterward for stable operation.
In particular, major adjustments were needed to Open Loop Fueling for stable cold starts, and the stoich AFR vs Ethanol Percentage table needed to be rescaled.

This solution may not apply to the 1.6L, or 1.8L models found outside the US.

雪佛兰科鲁兹e83模块支持E85传感器？