Tapping noise from engine at high rpms

[Scott.T]

I have looked for a while and couldnt find threads pertaining to my tapping sound. When driving the truck around town and the back roads from anywhere up to 60 mph it is fine. If I drive on the interstate at 70+ for any period of time it makes a tapping sound. I usually dont notice the tapping sound until I come to a stop after driving those speeds, if I rev up the tapping gets faster. Once I start driving at the normal speeds or 45-55 mph the tapping dies down and goes away. It has been doing this since I have bought it but I havent payed no mind to it since I rarely drive on the interstate. I was thinking it could be spark knock? I do get a CEL light every once in a while with 2 codes, one for the knock sensor and the other for egr. I figure it would more likely be the knock sensor causing this problem. I have read though that it is a common problem for our trucks to get knock sensor codes every once in a while and it be nothing, a bad connection or something. From what I have read as long as it idles fine and not dying at stops that the knock sensor is usually still working fine, so its not worth replacing it since it is a pita to do. What are your guys's takes on this? Could it be something else, spark plugs, plug wires, cap, rotor? I havent given it a tuneup since I bought it, just gave it a seafoam treatment, changes the oil and transmission fluid so far. Any thoughts will be appreciated.

[Slartibartfast]

I've heard that the EGR can 'flutter,' the mechanic who did my timing belt said mine was doing it, so I cleaned it out. My only other thought is that the lifters might be worn out. How many miles are on it?

 

The knock sensor can trigger the engine's limp mode IIRC (won't rev over 3k), so that probably is something to take care of.

[ahardb0dy]

When driving at the higher speeds when the tapping is more evident, do you notice any loss of power?

[Scott.T]

It has 210,xxx miles right now. When the ticking is heard there is no loss in power, it runs exactly the same, just makes the noise, it goes away shortly after driving at slower speeds, I would say within a minute or so. It runs strong and smooth, just has the normal ticking sound from a cold startup that only lasts a few seconds. This other ticking sound does not sound like that though.

[ahardb0dy]

so no loss in power so it's not a bad ignition wire. I was going to say oil pressure but it would normally be the opposite, low at low RPM and higher at high RPM.

 

What oil brand,grade and filter are you using?

[Scott.T]

I used penzoil conventional 5w30 and a purilator oil filter

[joa_taste]

Ive had this same problem, with same year pathy. recently changed the oil and that sound is gone..maybe its lack of oil?

it doesn't sound like a engine knock or tick or ping right?

[Kyle94]

My engine kind of taps when my oil gets low (uses about a qt somewhere every month or about 1k miles...) at a higher RPM. check your oil level and add if necessary!

[Towncivilian]

It'd be a good idea to check your engine oil level at every gas fill up and top off if required. If your oil consumption is excessive (more than 1 quart per 1000 miles), change your PCV valve and check for leaks.