UK Car Repair: vauxhall vectra 1600 16v excessive fuel use, vauxhall vectra, temperature control unit

Question
i have a 1997 vectra 1600 16v, the engine management light came on recently and the lamba sensor was faulty, had that changed car is flat when pulling away and using petrol at a rate of 14 miles per gallon, so far the egr unit has been changed and the temperature control unit, it is a bit better but still having fuel problem and lack of power any ideas please?

Answer
Hi Graham, did the light go off on the dash after the new lambda was installed ? There can only be be couple of reasons for the symptoms you describe, the most common of which is a broken catalytic converter which will block up and cause the car to drive sluggishly and be hard to start. To check this when the car is cold knock the cat with a rubber mallet and listen for rattles (if broken it would sound like stones inside it) then start the car and rev it hard (if the cat is blocked then it would sputter). Another reason is a misfire which can also cause the cat to break up due to massive amounts of unburnt fuel going directly into it. To check if the engine is only firing on 3 cylinders, start the engine and very very slowly bring up the revs to around 2000, if you feel a vibration through the car then you are running on 3 cylinders and would probably need a new coil pack. Let me know how it goes - Paul