98 Passport sounds like a Harley

[SanAntonioPassport]

While accelerating at moderate speed (40-45 mph) on the highway today my 98 Passport went from a quiet, peaceful ride to a loud, thunderous beast in a split second.

It's as if I'm now driving without a muffler. However, the loud noise of the engine running it in the front of the vehicle, driver side.

I'm guessing it's either the exhaust manifold (possibly cracked)?

Or maybe the exhaust downpipe (possibly cracked)?

Or perhaps the caty converter located under the driver's side floorboard.

Any thoughts from similar experience are greatly appreciated. If it is the caty, how hard are they to replace?

P.S., the vehicle has 98K miles on it.

Thanks in advance.

[Cat Fuzz]

Something in the exhaust system has broke. I believe they are all bolt together components so it is possible to fix it yourself. Buy some PB Blaster and soak the fasteners with it before disassembly and you might avoid breaking them.

[Gizmo42]

A few things it could be. Its fairly common for the flex joint at the y-pipe to get old and brittle then finally break. Could be the gasket at the manifold/head pipe joint. One member on planetisuzoo found the weld at the flange on the manifold where it bolts to the head pipe had split. He welded it back up.

[Uncle Pow]

Originally Posted by Gizmo42

...the manifold where it bolts to the head pipe had split. He welded it back up.

I had this problem. Sounded just like what you describe. Find a good muffler shop and they can fix it in one day. I had mine fixed and 2 catalytic converters installed (bought myself) for $250.

[fourwd1]

Originally Posted by Gizmo42

A few things it could be. Its fairly common for the flex joint at the y-pipe to get old and brittle then finally break...

X2 on the flex joint, they dont last.
Had one go on my Trooper last year and now on the Maxima.