The headlight wont come on when pulling a CFI sled. It is controlled by the chassis relay which keeps power off till the system has good idle. Check fuel pressure. If it comes up well, within a couple pulls, it shows the alternator/charging/fuel pump are working decent.
After that it's best diagnosed by DigiWrench to check for sensor and 2X/5X stator coil malfunctions.
On an 05 check the ECU for corrosion down in the lower right corner (opposite the baro pressure sensor). It wouldn't be the first one attacked by road salt and such. Some of the components protrude through the sealer and are prime to let in moisture.