i have been stumped the past few days i have a 03 ford ranger 4 cylinder, before i bought it, it was going through coil packs and would run fine for a couple weeks then run on only 2 cylinders when I bought the car we tested the ECM and it was giving a weak single to cylinder 2&3 but giving a good single to cylinder 1&4. after that i buy a new ecm and program it and it still has the same weak single to cylinder 2&3, i re-ran new wires but no luck, it threw no misfire codes