2000 ranger with 3.0 flex fuel with misfire on 6. 134000 miles. Replaced plugs, wires, coil pack. Resistance on injector is 12 ohms in line with others. Checked compression on 6 and it was 90 compared to 130 on the others on that side. Ran seafoam through intake the. Ran it for a day or so and checked compression again and it was back up to 120 compared to 130 for the others. Still misfire, at least at idle. I cannot detect it at road speed. Found a split vacuum hose and repaired that. Have not done a vacuum test. Is there anything else to check or try before I pull the head. Others tell me it should be firing at that compression. Help please! Thanks!