Hello,

I am on the second of these broncos with the 2.9 and both have
lots of noise from fuel injection or something, but I sure don't
think its valve noise.  Sounds sort of similar though.

I remember a lot of those engines back then had mechanical lifters.
They put some in the pickups and even the Aerostar occasionally. I
don't know if the Bronco II could have had one also. If so, that would
be a huge source of noise unless adjusted regularly. A trained ear
would be able to tell.

You'll get other answers/opinions; but broken/loose valve keepers are
one (very expensive if not fixed) cause of valvetrain noise. I can
personally verify that one. Dropped valves are not conducive to the
block; head(s); piston(s) or your wallet.

Another is lifters and/or oil problems. The 2.9 has hydraulic lifters;
and they do "drain down" (get empty) when the vehicle sits for a few
days. That will cause a hell of a rattle for a short time until they
refill with oil. That's fairly normal. But if the oil pressure is low or
there's severe sludge blockage on the oil galleries feeding the lifters;
it ain't gonna stop.

If you have a Ford "oil pressure?" gauge in the dash; don't trust it.
It's just an idiot light in disguise. It only shows no-half-full; with
no real scaling. It will show "half scale" with anywhere between 5 and
80 lbs of pressure.

What I'd do on the valve clatter is add one of the commercial oil
flushes and run it for a few miles to clean out the passages (and the
lifters as well-they get gummy as well); then change oil *AND* filter.
Run the next oil change "short" (less than 500 miles) and do the flush
again; with another oil and filter change. (reason is that the sludge
may not gome out all at one time; and it can clog up the filter.)

As for other problems:
Automatic trans: The AO4LD is pretty weak as stock. Ford designed it
with 6 "planet gears" in the carriers; but the beancounters cut it down
to 3 each. A good rebuild fixes that and a myriad of other problems.
Raising the line pressure means harder shifts; but better life.

Manual trans : Also weaker than it should be. I'm no expert on these;
but I've heard that a later ('92 on) tranny is far better.

Rear driveshaft:  Weak CV joints and "high angles" cause problems. Most
any driveline shop stocks a replacement with double Ujoints that cures
that.

Other than that; it's a decent rig if you know how to maintain it. The
other major problem is a lack of aftermarket goodies. What's out there
is either damned good but pricey or stuff you wouldn't want on a phoney
riceracer. ( I saw a Festiva with a wing and the rest of the horseshit;
about gagged.)

Hope this helps