2007 HHR 2.2L running on a 2010 HHR FFV ECM (E37 with VVT disabled). Drove vehicle for several hundred highway miles over the weekend on both E85 and E10 and in both cases the DIC mileage reported is considerably lower than actual mileage measured. On E85 the DIC reported 18MPG, I measured 24. On E10 the DIC reported 20MPG, I measured 27.
It is also throwing a DTC P0171 Fuel Trim System Lean code on both E85 and E10. (commanded AFR looks normal)
Both of these "clues" would point me to look at a difference in injector flow rates...but both tune files have the same value (3.51 g/S if memory serves).
I'm really more concerned about the mileage reading being so far off...is there some other parameter in the tune files that would effect this?
It also seems to take an unusually long amount of cranking to start...if that is also a clue.
Bill