UK Car Repair: petrol smell, air mixture, o2 sensor

Question
Hi paul i have a 02 astra 1.8 16v and theres a strong smell of petrol when i poen the window i have looked every
where but still cant trock it down and how do i alter the petrol/air mixture as its running rich

Answer
Hello J, are there any lights on on the dash? You cannot alter the mixture because the ECU controls the mixture with signals sent from various sensors. Usually, if the car is running rich, the O2 sensor is at fault. If you allow the car to idle and very very slowly bring up the revs, it should rise smoothly. If it does not and you feel vibration, then it may mean a misfire (only firing on 3 of the 4 cylinders) - Let me know the outcome and we can go from there. - Paul