My exhaust was blocked and the Catalytic converter bad, it was removed and I feel the engine has more power now, I plan on replacing it soon, there is no CEL light on even when it was blocked but the car had always consumed fuel roughly between 10-12mog, which is supposed to be 15-17mpg. The mechanic said the catalytic converter is responsible for the high fuel consumption, I asked him how much it is sold and he said 60k, the question to all gurus here is "does catalytic converter really reduce mileage?"

Which car model?... Please type in English..I see autologic here so I'll leave him to it

Doslop:
My exhaust was blocked and the Capra lyric converter bad, it was removed and I feel the engine has more power now, I plan on replacing it soon, there is no CEL light on even when it was blocked but the car had always consumed fuel roughly between 10-12mog, which is supposed to be 15-17mpg. The mechanic said the catalytic converter is responsible for the high fuel consumption, I asked him how much it is sold and he said 60k, the question to all gurus here is "does catalytic converter really reduce mileage?"

You need to state your car model to get better response.
Blocked cat will reduce fuel mileage drastically cos the blockage will acts as restriction to flow of exhaust .
In extreme case of restriction it can damage the engine completely!!
Your car require good inflow and outflow just like human being to be in good state of health.
To protect our evironment u can replace the cat.

menstrualpad:
Which car model?... Please type in English..I see autologic here so I'll leave him to it

It's Acura MDX 2003

Doslop:

It's Acura MDX 2003

Cc honmusa finish the work sir.

Still waiting for the gurus in the house, please help a brother out

Go and replace your catalytic converter

There is no way your catalytic converter was blocked without a code. But it should have no bad effect on engine you should still have a code from the downstream oxygen sensor

sultaan:
There is no way your catalytic converter was blocked without a code. But it should have no bad effect on engine you should still have a code from the downstream oxygen sensor

true. P0420 should have triggered when the cat was blocked

sultaan:
There is no way your catalytic converter was blocked without a code. But it should have no bad effect on engine you should still have a code from the downstream oxygen sensor

Not every time !!!A times some prevailing issue elude the engine management system .90% cars from Cotonou already have the cat removed and not all of them have catalyst code (P0420) triggered even with a well functioning downstream O2 sensor ,I see this all the time!!
Also Cat monitor test always take a longer Drive cycle to complete relatively and during the time the test is not completed , DTC related to the issue will not come up in case the cat is bad until the test is completed

@OP, in response to your question, Yes, a bad/blocked catalytic converter will reduce mpg, slow down the movement of your vehicle amongst other issues.
While it is recommended to replace it, you really have to open your eyes when getting a tokunbo catalyst as there are many "cloned" catalyst in the market.
Your reported mpg is not unusual for the vehicle in question though it depends on how you drive etc.

honmusa:

Not every time !!!A times some prevailing issue elude the engine management system .90% cars from Cotonou already have the cat removed and not all of them have catalyst code (P0420) triggered even with a well functioning downstream O2 sensor ,I see this all the time!!
Also Cat monitor test always take a longer Drive cycle to complete relatively and during the time the test is not completed , DTC related to the issue will not come up in case the cat is bad until the test is completed

The catalytic converter does not just backlogged with carbon at random, a issue with misfire will likely be triggered when sunburnt fuel gets to the cat first

Thanks for your response guys, I really do appreciate.