....OK, my 99 Eddie Bauer Expy, 5.4 with Edge on canned tune 2 and no other mods just today developed a loud tapping, clicking noise in the general area of the right rear upper engine. This is just in front of the passenger seat. I can trace it to the area between the 4 wheel drive acuators and the throttle body. Engine was hot so I could not really get my hands into it to feel for a vacum leak. I suspect a vacum leak because it needs the brake pedal depressed or the gas on to be there.

Here is what I know....

It increases with engine speed.

Only occurs with the gas or brake applied, when foot is off gas, noise goes away.

Only occurs when in forward or reverse gears, not nuetral or park.

My truck is out of commision while I am doing some maintenence this weekend, and I really can't afford to have the wife's Expy down as well. Any help at all, point me in the right direction.

By the way, I did do an extensive search but every one has a click or tap and we all spell horrible, especially "vacum" (I don't even think I got it right )

 

lol. first thing you'll want to do, since i think the 99 5.4's are the notorious ones for launching plugs, make damn sure its not a plug ready to launch. then i would look for an exhaust leak, my 4.6 had one that seemed intermittent like you mentioned.

it may also be a dirty lash adjuster (they are hydraulic, some people have had luck running a small amount of ATF thru them on other model vehicles for a few hundred miles before the oil change)

 

Got it figured...


...it was a loose plug. Dang, we have 4 5.4 F150's in the driveway and the combined milelage is over 500K and this is the first blown plug we have EVER had.

Now we did have a 97 4.6 that gave us fits like a colicy, teething baby until we gave it back the Motorcraft plugs. And that was on a 2500 mile road trip with the wrong plugs installed an hour before we left...OUCH

Well, I am planning on a plug change and TB cleanup next week for this rig. Sounds like it needs it.

Thanks

 

Do NOT use antiseize and torque the plugs to 28 ft/lb.

 

i use NGK plugs rule of thumb printed on their box. i believe it was 2/3 turn roughly from finger tight.

 

x2 x2 x2!