My 2002 F250 with the 5.4 (215,000 miles) has a loud tap upon start up, only on the passenger side, heard best in the wheel well. It only lasts about 30 seconds to a minute. Any ideas? It occasionally rears it's head driving around town but only intermittently. Just drove it 275 miles, at 13mpg, truck runs fine, just annoying.

Thanks in advance.

 

High mileage could always be a lifter noise. The 5.4 also had cam phasers. They are driven by oil pressure and when they wear out don't keep the correct tension on the timing chain. Mostly noticed at start up after sitting a while, motor will sound design like a sewing machine until oil pressure is built up. A single tick on one side can also be traced to an exhaust leak at the manifold.

 

Like the last guy said, it could be a lifter. I would check and see if any of your exhaust manifold bolts are broken though, a very common issue on those engines.

 

Op's 5.4 is an 02 so no cam phasers those didn't show up till 05

 

I was taking a guess, I never owned one. See, you learn something new every day!

 

+1 on those pesky exhaust manifold studs... they snap off over time creating a small gap.

Once the engine warms up the metal expands and temporarily closes the gap

 

Either exhaust manifold studs or a cracked passenger side exhaust manifold.

 

You could be on the verge of spitting a spark plug out. My dad had an 02 that developed a tick at @75k miles. It was intermittent at first, then continuous, then one day, it sounded like the right front tire exploded. And the truck started missing with a very loud lick. He thought he had broke a rod or something. It had shot out the passenger rear spark plug. Honestly, that's probably your best case scenario. The repair kit was @ $35 back then and took @ 45 minutes to repair, and some gorilla glue to repair the coil. Sure beats changing lifters or messing with corroded exhaust manifold bolts. But with your mileage, there's a good possibility of the valve train needing some attention somewhere. Could try some thicker oil or STP oil treatment just to see if it helps. That STP is good stuff.

 

So no cam phasers on my 02 5.4? Thought that would be the problem?

 

See above. Take a video and post it.