Dear Vivek,
You should always give it a try with one by one step at a time. Get the sensor change, which i assume is far cheaper than catalytic itself and its installation will also be in few hundred dirhams and then tell us what happened.
i agree these guy are at par with leading service provider and the fact that they have their own spare parts too so dont have to worry from where will they arrange the parts.
To behonest, Mazda 3 is sucha problem free and low cost maintenence car that you wont regret ever.
Had one in past used for 3 years with every quarter enoc/eppco service for 150 dhs, thats it.
Just make sure car you get is clean and not badly maintained with shortcut jobs and not involved in any accidents.
You will enjoy this sweet ride for years to come.
Let the car run idle for few minutes with petrol cap open, so that if any air bubble formed or backpressure created will be release and drive. See if it helps.
If it doesnt see any mechanic and ask him to remove fuel pump delivery hose at hose and let it throw few ml of petrol with pressure so that it can clear any air build up inside.
my mazda CX-7 has started jerking when cold start which is pretty unusual as first i thought maybe it could be the breaks issue which is not the case and it only happens on cold start.
any clues
thanks