One thing to understand about the 4.6,.. a 4.6 is a 4.6 is a 4.6. No matter what its in,.. Mercury, Ford or Lincoln. Triton, Intech, Mustang, Truck, Crown Vic,.. what ever. They are ALL the same motor. The main difference between the models will be the intake. Each chassis had its own unique intake and induction assembly. But from the heads down,.. they are the same motor.

The are 2 primarily different 4.6 motors. The 2v and the 4v. 2 cams and 4 cams. There are only 2 different versions of the 2v. The NPI and the PI. All original 2v 4.6 motors from 92 - 98 no matter what they were in were NPI (Non PI) motors. Only the Mustangs got PI (Performance Improved) motors in 99. The only difference between the NPI and PI motors are the heads, cams and lower intakes. The upper intakes usually stayed the same. 4.6 trucks did not get PI heads until 01 model year.

Aside from all the confusion describing the difference between the NPI and PI. EVERYTHING between these motors is interchangeable,. visually they all look identical unless you know what to look for.

2003 you should have a 2v 4.6. No variable valve timing. Aside from the intake,.. the block and heads should be identical to whats found in 99 - 04 Mustangs. The newer model 04+ had a 3v 5.4 available. These did have a version of VVT (Variable Valve Timing).

Not sure about the trucks. But in the Mustangs the 4.6 did not have a smog pump. Its a very efficient small motor.

Cant really hear anything distinctive from the first video. What ever was used to record the video couldnt reproduce an accurate audio sample. Sounded like a lot of distortion to me. (No offense).

The second video I could make out a humming noise from the intake duct. Sounded like it has a crack or leak in it somewhere and if so would be very bad. Any kind of intake leak between the MAF and TB would produce a lean condition as the engine is getting more air than what the MAF is reading. The front O2's should detect this and the computer will compensate by turning up the fuel causing the motor to run pig rich. When in fact,.. the air coming in the motor has not changed at all,..only what the MAF is reading has changed.

Not saying this is for certain your problem. I am not there.

Check to make sure the air intake is sealing correctly between the MAF and the TB. Make sure nothing loose floating around inside of it,.. (Lost tools?).

At 120k it would not hurt to pull the air intake assembly off entirely and inspect the TB blade. The whistling/humming noise could be from air by passing a dirty blade that is choked with gummed up debre.

Something else that noise sounds like from past experience. The PCV on these make an awful racket when they go bad. I thought I had a leaking intake once when it turned out the PCV was bad. When replacing it make sure the grommet to the valve cover is still in good condition else replace it with the pcv. Check the vacuum line coming from the intake to the pcv as well and the there should be another 'bypass' vacuum line from the front side of the IAC that goes into the air intake in between the MAF and TB. ALL vacuum lines no matter how miniscule are crucial on 4.6 motors. The sensors and EEC are extremely sensitive to vacuum signals. If even remotely questionable (Dry, hard or gummed up) replace the vacuum lines.

My money is on the PCV. But bare in mind,.. I'm not there. You are.

Hurst