Q&A

P0301 means misfire detected on cylinder #1, for 300 consecutive revolutions. P0316 means the misfire was detected in the first 1000 revolutions. It all means you had a dead miss on #1. It could be a bad sparkplug, a shorted to ground sparkplug wire (likely). You didn't tell us which particular engine you have, there are 3 choices for 3.0 liter, like Flex Fuel, for instance. The high output engine has an ignition coil on each cylinder, the one on #1 could be bad if that's the case. If it doesn't have a coil on each cylinder, it's probably not a coil but a wire or plug. there's the possibility it's an injector problem too, also possible that there's a mechanical problem like a bad engine valve but not likely. I once found a faulty ground side circuit for the injector in a car like this which caused a similar problem. check the sparkplug and wire first, though before figuring whethe there's a poblem with the injector.

changed fuel filter and codes (P0301 and P0306) disappeared. Changed on Ford Taurus at 101,000, may have been original filter. Tank side gas was dark brown.
Thought I was going to have to change out the spark plug wires and ignition coil.