98 Isuzu Rodeo Ticking/Rattling problem solved finally

My 98 Iszuzu Rodeo (144,000 km) was having the same loud ticking, rattling and "lifter" problems are mentioned often in this forum. Replacing the timing belt and tensioner, PCV, engine complete flush, and cleaning the EGR, reduced some of the noises but the "loose bolt", "spun bearing", rattling sounds remained very loud around the 2000-2500 rpm engine mark. The problem was
finally solved with a couple of hammer blows today.... A bracket welded on
to the exhaust pipe holds a round counterweight designed to reduce exhaust
pipe vibrations. One weld on the bracket had broken and the loose edge was
just touching the exhaust pipe. 2500 rpm engine vibration set off the rattling noise. Two hits with a hammer bent the bracket edge back from touching the exhaust pipe. Problem solved at last and all is now nicely quiet. Look under the front passenger door sill to locate the bracket and the circular counterweight attached to it. Cheap fix for a perplexing noise problem.

I have that exact sound at 2500 rpm. I'll have to roll under and and take a look.

Well I inspected and I didn't find a donut, but did find a heat shield that is mounted with a clamp and the part of the shield that is under the clamp had started to rust away. So I tossed on another hose clamp and the sound is now gone.

I've heard of others having problems with these as well. I bet most would never think to look at those. I know I wouldn't.

The bracket with the "hockey puck" circular weight was attached on the
passenger side exhaust end bolted connection of the catalytic converter with the exhaust pipe, that joins together with the driver side exhaust and feeds into the muffler. The heat shield before the convertor had earlier rusted/broken loose and was clamped by the previous owner to reduce the rattling sounds. I do not know if the bracket with the circular weight was a later addition by the manufacturer to reduce vibration and noise problems. The other heat shield just past this bracket also seems to be breaking loose and will need some sort of clamp to stop new rattling sounds from developing. My truck remains nice and quiet after all these front exhaust repairs. Some of those unusual "engine noises" could be from rusting/cracking exhaust shields and brackets that really vibrate at 2500 rpm.

Also if you have a skid plate under the tranny, take that off and check for broken heat shields.
These heat shields tend to fall off and get pinned under there.