Hey all. 2004 F150 lariat 5.4 4x4 122000. My truck has been running kind of crappy for a couple months. Gas mileage down to 7mpg (mostly around town start stop 10 minute rides. NO CHECK ENGINE LIGHTS. No pending codes. Oil pressure by "dummy" gauge fine. Oil changed every 5000. Mobil 1 full syn 5w-30. Motorcraft filter. I know it needs a plug change and was going to conquer that after Thanksgiving. The other day I left my house drove about a 1/2 mile. And a REALLY LOUD TAPPING noise started. It seems to be coming from the right side of the engine. Continued driving after pulling over to check basics. Tapping sound CONTINUES. Never gets louder but does speed up with acceleration. Has always had the "TRITON TICK" BUT this is different almost like a broke lifter. But stupid me I'm assuming if it was that I'd have a CE light or white smoke. But I have NONE of those things. Anyone got a guess where to start looking. Other than the LOUD tap. Truck runs the EXACT same as before. Thanks in advance for any and all responses. KEEP ON TRUCKIN. 😀😀😀

 

Didn't by any chance crack the passenger side manifold did it? Not sure that explains the gas mileage though.

 

Sound like this ?

 

no. Way louder than that.

 

Pull the passenger side valve cover and inspect the cam for abnormal wear on 1 or more lobes. Hopefully it's only a bad follower or 2 and you caught it early before it trashes the whole motor.

 

Regular tapping at the same frequency or irregular?

Heavy or lighter sound? i.e, a quick, light tapping like a valve or follower? Clacking like something is hitting against something else? Heavier thunk-type sound?

Front/rear/top/bottom of motor?

 

I bet the cam chewed up a seized roller follower. Take off the passenger valve cover, probably the back cylinder.

 

wouldn't that kick a CE light or a code though ?????

 

Also u guys are saying Passenger but its WAY louder Driver side

 

seems to be the same frequency. Driver side. Quick but loud. Definitely a tap not a thud or knock