So I have a 07 non h.o. 4.7. This p0506 code pops up about every tank of gas between 125-250 miles. I have replaced the IACV idle air control valve two times now, it's right below the TPS. Code is still being thrown. I have checked for vaccum leaks via some brakeclean, even pulled off some hoses, but it seems a vac leak would make the idle faster right... I have seen it says steering pressure switch can cause this and also exhaust blockage, but I pulled a vac hose and idle we t up t ok about 1900 rpms. With the code on my truck puts at 700rpm idle speed. Normal, even with ac on/off or heater. I have not checked the pcm though or checked voltage at the IACV. I dont really know where to look next, I'd appreciate any and all advice.