More torque & top end out of a 99 4.0L

[willyb]

The proper way to test a Catalytic convertor is to backpressure test it - invloves drilling holes in the exhaust. But if you want a quick and simple way to test it just got pound on it (NOT WHEN IT'S HOT!!) - just hit it with your fist or another object with 'medium' force (Not trying to kill the thing). If it rattles - sounds like you have golf balls in there, then you may want to investigate further. I'd try that first.

*This method is not 100% accurate - just simple....

Will.

 

[bjoehandley]

Mine sounds like that just starting it, what is the "warranty" on factory installed catalitic converters? Friend of mine told me they have to replace ones that go bad before they hit 80K by law. That sounds right, but I'm not too sure.

 

[Slip Kid]

Also check under the hood, you might have some vaccum tubes disconnected or missing.

When I first bought my 87, it wouldn't do 85mph, I found a couple of unhooked vac tubes, and then it went as fast as I wanted it to. check the tubes for cracks/leaks as well.
That 99 should RUN if everything's working ok.

 

[willyb]

Mine sounds like that just starting it, what is the "warranty" on factory installed catalitic converters? Friend of mine told me they have to replace ones that go bad before they hit 80K by law. That sounds right, but I'm not too sure.

Federal law is 80,000 miles/8 years...

Will.

 

[bjoehandley]

Sounds like I've got just over 1500 miles to get mine taken care of.

 

[92AKXJ]

Howey, go see Kurt, Dan, and Noah at 5 Star Automotive, on Lake Otis. They'll get you fixed.