Hi All,
I need some advice.
About 4 months ago the MPG on the Jazz suddenly dropped from an average of about 45-50mpg down to barely 33mpg. I understand that the cold weather has had an impact on it as the ECU compensates with more fuel and the use of the heater etc. But I would have thought that at most this would reduce it by 5-10mpg. We've seen the dash MPG reading up to about 65mpg before, though I do take it with a pinch of salt.
I just don't understand it. There are no obvious faults with the car, all seems to be in order, we use Shell normal unleaded and it has new tyres. The only thing I can think of is that I have a carbon T1-R cold air induction filter on it. It hasn't caused any problems before and having had a look around it, nothing obvious seems to be blocking it.
Any ideas?