My 4.2 engine started making 'bad' start up noises after a 3000 mile
trip and oil change right after.  I thought the engine got toasted. :-(

It turns out I didn't pay attention and just bought the 'on sale' oil
filter which was a Fram.  I then read about and remembered that Fram
filters have drain back issues....

Sure enough, I went and just changed the filter to another brand and
'all' the noises went away.

Worth looking to see if your filter is that Fram color.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
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What mileage?  Has any engine work ever been done to it?  What grade
of oil are you using?

Just to be safe you may want to use a real pressure gauge and monitor
oil pressure at all temps and driving conditions.

It does sound like an oil filter drain back issue on the surface, but
if other filter(s) have yielded the same results, then that's pretty
much out.

You may have excessive bearing clearances, leaking timing chain
tensioner(s), valve lifter leakdown, or a weak oil pump that is
starting to manifest itself as longer pressureup times.  I would look
at a real pressure gauge reading before any other testing.

Can you distinguish the difference between timing chain rattle, valve
lifter noise, and rod bearing noise as they relate to a loss of oil
pressure?  I know you said it sounds like rod bearing noise, but I
wanted to see how sure you are of that observation.

Lastly, I don't know anything about the Vin K 4.0.  Is that a DOHC?
Is it new for 2004?

Toyota MDT in MO

Maybe a valve rapping because of a collapsed lifter.

Check your oil filter.  Some cheap filters have issues with the internal
valve leaking, so the top of the system drains down from the filter while
the car is sitting, and then it takes a little time to come up to
pressure again.

Then try a different kind of oil.  If you're using a synthetic, try a
petroleum type.  If you're using a petroleum oil, try a synthetic.
--scott