Confirm the catalytic converter is actually clogged
Check for engine misfires, oil burning, coolant burning, or rich fuel mixture
Scan for trouble codes with an OBD2 scanner
Inspect the exhaust system for dents, leaks, or collapsed pipes
Replace faulty spark plugs, ignition coils, injectors, or sensors first
Repair any engine issues causing excess soot or fuel contamination
Use a catalytic converter cleaner only if the clog is mild
Add the cleaner to the fuel tank exactly as directed on the product label
Drive the vehicle at highway speed after using the cleaner
Perform a forced regeneration if the vehicle is diesel and equipped for it
Remove the catalytic converter for inspection if symptoms persist
Clean the converter off the vehicle only if it is reusable and not melted or damaged
Replace the catalytic converter if it is melted, broken, or severely clogged
Clear diagnostic codes after repairs
Test drive and recheck for power loss, warning lights, and exhaust flow issues