89 Bronco Clogged Catalytic Converter?

[Eddie89]

I have a 1989 Ford Bronco 5.8L 351 that starts but idles rough and as soon as I give it gas it dies. There is a hissing sound from the catalytic converter and when I pulled the O2 Sensor today, the rough idle goes away and it doesn't die when giving it gas. I've replaced all the vacuum lines as well as some were leaking. I've also tested the EGR components, IAC and ICM and all check out.

Does anyone have an experience similar to this? Before I replaced the cats, I just want to make sure it couldn't be something else.

Thanks!

 

[L\Bronco]

Hey Eddie, that is a textbook plugged exhaust from your description, usually its the cats, once in a while its a muffler. Id drop the exhaust and look at the inlet side of the cats, its usually very apparent.
Good luck
Cheers!