I have an 05 ranger w/ the 3.0L engine. It started running rough at idle but fine above 1500rpms(or at least I can't feel the miss anymore). I then replaced air filter, plugs, wires, and fuel filter about 4 months ago. It got a little better but the CEL is constantly back on now and the idle is getting worse. Here are the codes I pulled prior to clearing them; P0300-Random/Multiple misfire, P0304-Cyl 4 misfire, P0305-Cyl 5 misfire, and P0316-Misfire Detected 1st 1000 Revs. I have had these codes read by Autozone, Advanced Auto, and now my own scanner. Now I erased those codes and restarted the truck with no CEL showing. About 10 secs the CEL came back on flashing with only one code at first which was the P0305. Now comparing to other forum entries on this same issue, I do not have white or black exhaust smoke. I have tested wires and plugs again...nothing. I have also bought a multimeter and tested my coil pack. Cylinders 1&5, 2&6, 3&4 are paired together on each coil section. For 1&5 and 2&6 I got exactly 11.35k, but I got 11.21k on the back coil with 3&4 on it. A few minutes later I got 11.21k on both the fronts and 10.99k on the back one. I know that each coil is supposed to be between 8.5 and 14.5, so they are in range. But the one being different throws me off. Can anyone make any sense of this. I don't want to just throw money at parts until I get lucky. Thanks.