Can a cracked catalytic converter cause an engine to run rough?

[#1]

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Can a cracked catalytic converter cause an engine to run rough?

Does the downstream oxygen sensor help determine how the engine runs?

My truck runs rough after revving it up a bit. I've noticed a bad exhaust leak that sounds like it is coming from under the heat shields on the catalytic converter.

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[Wicked_Sludge]

the rear O2 sensor only monitors cat efficiency. the forward O2s are how the truck determins A/F mixture.

a leaking cat could cause drivability problems....especially if its broken or clogged inside (which is likely if its damaged).

 

[04 EDGE]

a cracked converter is not going to effect how the engine runs, it will only cause an exhaust leak.

this was somewhat common on 2.3 and 2.5 cats in the mid to late 90's

 

[cocoasranger]

If the honeycombed catalytic bed inside the converter is cracked it can create enough back pressure to seriously affect performance. This is what the "converter test pipes" were supposed to be used for; as a temporary test to see if the performance problems would cease before installing a pricey new converter.