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Clogged catalytic converter

Is there any way to solve a clogged catalytic converter, like adding an additive? The car is a Ford Focus SE 5-speed with 90,000 miles.

Take the converter off and punch a hole through the inside. (depending on emissions standards in your area)

There is only one easy fix. Get a new converter. You don’t need to go to the dealer. Third party converters are regulated by the feds so save your money and replace what you have.

Note: How do you know the converter is clogged? I fear a lot of good converters are junked because someone wanted to make a dollar.

Is there any history of problems with your car? It really should have a clogged converter at 90K unless something caused it.

Make sure your exhaust pipe is not flattened somewhere. Have the whole system inspected. If it is the convertr, get an aftermarket model installed. They are readily available for your car.

I’m no mechanic but I think it’s the converter. It’s making a sound that I don’t know how to describe from the exhaust. Kind of a steady puff, puff, puff. It smells like sulfur when it’s doing this.

puff puff puff sound often goes with a leak

You don’t want to punch out the catalyst in the converter and reinstall it on the car. This is a hack mechanic method of repairing a plugged catalytic converter.

First thing I would ask is if the Check Engine light is on?


catalytic converter will smell like rotten eggs. No additive would work…where would you add it? to the gas tank? anything that goes to the tank will go to the engine and then turn into fumes. Fumes can’t unclog something, its not vicks. A plugged cat can be temporarily solved by drilling holes in it.

Why not have somebody who MIGHT know a little more than you check the car over??? Like a Ford Dealer. Replacing or destroying $500 parts because you THINK they MIGHT be clogged is insanity…There is a quick back-pressure test that PROFESSIONAL mechanics can perform to verify the condition of the converter…They simply remove the front oxygen sensor and install a pressure gauge…

You have that statement a bit wrong.

A plugged cat can be 100% ruined by drilling holes in it is what you actually mean.

Drilling holes in it doesn’t solve the fact that it was plugged up.

What you should be asking is:

What plugged up the catalytic converter?
Has the cause of the converter being plugged up been resolved before you replace it?

Drilling a converter solves nothing, and will only cause the car to fail an emissions test, if it needs to pass one in order to be registered in the state.


If the converter is clogged up, the most common symptoms are low engine power, limited top speed (sometimes as low as 10mph), limited engine RPMs(often won’t rev beyond 2k to 3k rpm in neutral), and a check engine light for excessive EGR flow. Are you getting any of these symptoms? A sulfur smell can mean something has contaminated the catalytic converter, but not necessarily plugged it up, and the puffing sound may be a tuning problem or something normal that you have never noticed before, if it’s at the tailpipe. If the noise is under the car, you have a leak somewhere.