Mine is doing this, hunting/juddering on steady throttle... asked the Mrs. last night to try to/from work today locking it in 5th (doing it in 6th between 110-140kph) and seeing what it does. Also replaced Fuse 27 with the kit (was cooked), fuel pump drive unit (preventative), evaporator canister (gummed up full of dirt), cleaned the MAF sensor and reset everything and tested the modules again. No more codes.
Ran it last night at up to around 80-90kph on partial and full throttle, including full RPM in first, with the OBD scanner live. No codes. It did record one instance of misfiring on Cylinders 2 & 4 on the PCM at 13mins in at 1675rpm, OBD module shows 1 of permissible 65500 instances of misfiring in the current drive cycling, with misfiring detection/calibration/management ok. Will take it a long run myself over the weekend and check the OBD readings.
Looking at eliminating:
- road speed effects by trying different gears
- monitoring health of Coils 2 & 4
Car is 5k in from a clean air filter and 7k away from needing plugs. Just priced up plugs, leads and coils... ooft! Will be doing the plugs plus whatever is damaged, coils were ~$160 each as were the cables (ford parts website... will look for other sources). Will monitor and if it persists in the OBD recorder, I will try swapping the coils round to verify.
Car running ok otherwise, better for binning the evap canister and fixing the fuel pump relay electrics. Hope that helps. 2014 Stage 2 Roush SCrew with 153k km.