Good afternoon. A month ago, an important maintainance was done to my car and it left the mechanic with a better compression and power. However, it has recently occurred to me that, after accelerating at 3000 rpm on a straight road and braking, the car lost power and revolutions dropped, as if it were about to stall. Even more, knockings are heard from the engine and the 2nd gear is powerless. Spark plugs have been checked and they are working, but numbers 2 and 3 have a problem of fuel burning. I do not know if it has to do with more air than necessary entering through some hose or if there is another kind of problem. The hydrovac has been checked and it is alright. Another thing is that the exhaust has got a strong smell. I would appreciate your help.

The Catalytic Convertor has been found to be the issue while being checked by my Mechanic. The main issue is that the car skip accelaration while on gear when trying to gain speed quickly and loss of significant power as well. I've been told that my Catalytic convertor was clogged and needed to be removed or Cleaned or even replaced by my Mechanic. But i was also told that the issue might be the Oxygen Sensor as while proceeding with a car diagnostic, the issue was mentionned to be the Oxygen Sensor. I'm on the balance and need to quickly repair it as it's very frustrating driving a car with such issue.