Nissan Repair: Code P0420 infiniti I30 01, code p0420, infiniti i30

Question
Check engine light found P0429- Replace front tube assy
Light re-set, couldn't afford 950 quote. 1 month later check engine light came on again, noticed the car runs differently. Runs much louder, have to really push the car to accelerate, sort of like when a muffler is gone. The engine light went off but the car still runs loud . What is
a front ube assembly and could it be the cause of the current problem?  thanks

Answer
Hi Paul,

The code you supplied me tells us that the front catalytic converter needs to be replaced. I would seek an independent exhaust guy because he will be the lest expensive. Nissan lists this part at around $565 plus labor to install. After market should run half of that. The cat is clogged making the engine work harder and louder. Some friendly advice for the future, please do NOT use any type of fuel injection cleaner because they have a chemical that coats the catalyst in the converter, clogs it up and causes this code.