Bad catalytic converter symptoms - 2008 Hyundai Elantra

Question edited for clarity and spelling of 'catalytic'. No Cadillacs involved. :>)

Your neighbour is confused. Catalytic only go bad when they get blocked. As they start to get blocked up, you get the Engine malfunction light light up with a code and it happens gradually.

The back of the engine would be cool until it heats up.

Check for codes with a scan tool.

https://www.google.com/search?q=2010+honda+element+stalls+when+cold

and no acceleration

The most common causes for slow acceleration in Honda Element are clogged air filter, dirty mass air flow sensor (MAF), clogged fuel filter, fuel pump malfunction, faulty oxygen sensor, dirty throttle body, worn spark plugs and clogged catalytic converter.
Dec 14, 2021

Honda Element slow acceleration causes and how to fix it

Run a bottle of this for fun.

Dura Lube Severe Catalytic & Exhaust Treatment -16 oz ...

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A rattle sound means the insides are broken apart. If it’s clogged, the motor will run poorly and get very poor gas mileage.

a smell of rotting eggs --if you feel exhaust feels low flow / restricted --vehicle stalling --running rough---no start

Owen, is the engine light on or any codes stored in computer as this info would be beneficial in diagnosing problem.
My guess is your catalytic converter has begun to plug, which gives excess back pressure, robbing engine power.
check the links below.
Signs of clogged bad catalytic converter

https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwinzMW8mIXLAhXGMhoKHaWUD_sQFggeMAE&url=http%3A%2F%2Fwww.dummies.com%2Fhow-to%2Fcontent%2Fhow-to-troubleshoot-catalytic-converters.html&usg=AFQjCNE0zpmy0RHqRLsWNF2M6dO2xOkFHg

6 Symptoms of Failing Catalytic Converter DoItYourself com

Symptoms Clogged Catalytic Converter Loss of Power

Bad Oxygen sensor. Possibly _also_ bad catalytic converter. If less than (roughly) 70,000 miles, the converter is likely good. But your symptoms are 100% consistent with a bad oxygen sensor (which are sometimes attached directly to the catalytic converter). // Note: If you do need a catalytic converter, have it done at the Dealership. The ''muffler shops'' will install a generic (probably ''ceramic'') replacement, which could adversely affect performance, gas mileage, and _definitely_ not last more than a few years.

Improper Ignition Timing

Defective Ignition Components
(ignition coil/s, distributor*, distributor cap*, distributor rotor*, ignition wires, and spark plugs - NOTE:*Distributor-less engines do not have these components)

Lean Fuel Mixture

Defective Catalytic Converter
(Some symptoms of a bad catalytic converter:
Major loss of power over 15-25 mph.(does this speed sound familiar to you?)
Strong sulfer or rotten egg smell emitting from the exhaust.
Loud rattle being heard from inside the catalytic converter.

Defective Air Injection Components

Faulty smog pump if fitted.

Low Cylinder Compression.

P0422 Buick - Catalyst below threshold.

Catalytic converter is clogged or out of medium.

Replace it.


ACTUAL DIAGNOSTIC:

Fault Code Definition
Code P0422 indicates that the Bank 1 Main Catalytic Converter's emissions efficiency has fallen below the minimum allowable limit. This threshold is tracked by a Catalyst Monitoring Oxygen Sensor located on or near the outlet of the Catalytic Converter.

Symptoms

* Check Engine Light will illuminate
* In many cases, no abnormal symptoms may be noticed

Common Problems That Trigger the P0422 Code

* Defective Catalytic Converter
* Engine misfires have damaged the Catalytic Converter
* Internal engine damage resulting in high oil consumption and/or a leaking Head gasket has damaged the Catalytic Converter

Common Misdiagnoses

* Oxygen Sensors are replaced when the real problem is a damaged Catalyst
* Catalyst is replaced when the real problem is internal engine damage, which is producing elevated emissions levels
* Catalyst is replaced when a misfiring engine is the real problem



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P0422 - Catalyst below threshold.

Catalytic converter is clogged or out of medium.

Replace it.


ACTUAL DIAGNOSTIC:

Fault Code Definition
Code P0422 indicates that the Bank 1 Main Catalytic Converter's emissions efficiency has fallen below the minimum allowable limit. This threshold is tracked by a Catalyst Monitoring Oxygen Sensor located on or near the outlet of the Catalytic Converter.

Symptoms

* Check Engine Light will illuminate
* In many cases, no abnormal symptoms may be noticed

Common Problems That Trigger the P0422 Code

* Defective Catalytic Converter
* Engine misfires have damaged the Catalytic Converter
* Internal engine damage resulting in high oil consumption and/or a leaking Head gasket has damaged the Catalytic Converter

Common Misdiagnoses

* Oxygen Sensors are replaced when the real problem is a damaged Catalyst
* Catalyst is replaced when the real problem is internal engine damage, which is producing elevated emissions levels
* Catalyst is replaced when a misfiring engine is the real problem



Thanks for using FixYa - a 4 THUMBS rating is appreciated for answering your FREE question.!@##

Rotten eggs is usually a good sign your catylic converter has gone bad or is severely clogged. It will smell bad at first and then you will loose power over time.

P0422 - Catalyst below threshold.

Catalytic converter is clogged or out of medium.

Replace it.


ACTUAL DIAGNOSTIC:

Fault Code Definition
Code P0422 indicates that the Bank 1 Main Catalytic Converter's emissions efficiency has fallen below the minimum allowable limit. This threshold is tracked by a Catalyst Monitoring Oxygen Sensor located on or near the outlet of the Catalytic Converter.

Symptoms

* Check Engine Light will illuminate
* In many cases, no abnormal symptoms may be noticed

Common Problems That Trigger the P0422 Code

* Defective Catalytic Converter
* Engine misfires have damaged the Catalytic Converter
* Internal engine damage resulting in high oil consumption and/or a leaking Head gasket has damaged the Catalytic Converter

Common Misdiagnoses

* Oxygen Sensors are replaced when the real problem is a damaged Catalyst
* Catalyst is replaced when the real problem is internal engine damage, which is producing elevated emissions levels
* Catalyst is replaced when a misfiring engine is the real problem



Thanks for using FixYa - a 4 THUMBS rating is appreciated for answering your FREE question.