Ford F140 4.2 Do Engine codes P0305, P0306, and P1518 relate to each other

SOURCE: 07 lexus rx 350 with check engine light code p0304

Hi, did you ever get an answer? I have the same issue. Thanks.

SOURCE: 2000 ford escort ZX2 with P0171 trouble code.

I am working on the same problem. This 2000 ZX2 was idling rough and throwing a p171 code (bank 1 too lean). I hooked up a scanner to the OBDII port and you could see the O2 sensor at 0 or very low voltage and not switching and the fuel compensation maxed out which indicates a lean condition. Using a flammable Carb cleaner and the engine running I sprayed around the vacuum hoses until the idle picked up. I found a rubber elbow that connects to the bottom of the intake maniflold and feeds vacuum to the PCV valve. Replacing the the elbow with a suitable replacment from the auto part misc parts cards display had it running smoothly and the O2 sensor switching properly. Since this was happening at idle it was not the fuel filter which can cause a lean condition in upper rpms. It is not the MAF or the O2 sensor since it switches when not at idle. Also check the smaller vacuum lines that go to the evap control from the intake vacuum ports (back of manifold just below the throttlebody, most will be cracking if your car is anything like mine. I have also seen this problem with a bad PCV valve.

SOURCE: Trouble code P0171, P2195 Ford Focus

Sounds Like your o/2 is bad, are you burning e-8, try adding some injector cleaner/seafoam, and put a tank of preimu gas in then reset the code.