Originally posted on 2004-2008 forum but received no usable information.

my buddy has an 2004 NBS with 5.4 3v. Truck has about 178K miles and had the motor replaced about 6-8 months ago by an independent shop. He is throwing 2 codes: P0325 Knock Sensor and the other one deals with the cats being insufficient. He has a low grade slight stumble/missfire i believe. The mechanic is blaming the partially clogged cats to cause the knock sensor code. My personal mechanic/friend said that he'd seen numerous f-150's that knock sensor was not hooked back up to after motor work.

After looking under the hood today we found a few things that were not connected/hooked up. We replaced the driver side COP closest to the front 2° mount being broken. Tomorrow, we want to make sure the knock sensor is hooked up correctly, but unsure of its exact location. I know you have to take the air intake off to get to it but don't really know where to go after that.

Additionally, we put 2 qts of Mercon V into his transmission. No signs of leaking. Thought that was odd.

Also any other ideas about his truck would help

 

According to my Haynes (pos) manual, they are located under the intake manifold. There should be two of them located in the valley between the cyl. heads. The manifold must be removed to access them.

 

Yea, that's where the 2V's are as well -

 

You may be able to reach the knock sensor connecters and plug them in from under the truck by reaching up above the trans right at the rear of the engine. Might save you from removing the intake IF the pigtail is located out the rear of the valley. Also make sure the bolt that fastens the knock sensor to the block is tight and of course check for spare parts such as sockets, nuts, bolts, etc. in the engine valley. If these parts are present they can rattle around and send a false signal via the sensor to the PCM.