16v mpg dropped by 50 miles a tank

KITT · Post by **KITT** » Fri Nov 24, 2006 10:19 am

It seems after changing the battery in my 16v a month ago, the mileage I'm getting per tank has dropped from 350 miles to barely 300 miles

Could this be because the battery change reset the ECU or perhaps just a coincidence? Any ideas as to the cause as it's now costing me more money each week to get to work

twistedl · Post by **twistedl** » Fri Nov 24, 2006 6:56 pm

wish I got 350 out of a tank I only ever get 300

Polo Paul · Post by **Polo Paul** » Sat Nov 25, 2006 1:53 pm

I seriously doubt its anything to do with your battery change, its more likely dropped because of the cold weather that we've had. When colder denser air enters the engine it burns faster and uses more fuel. Happens to all cars but is more noticeable on more powerful engines. mines dropped by 5mpg, which over a tank is 45miles

KITT · Post by **KITT** » Mon Nov 27, 2006 9:14 am

I'm not convinced it's weather related as I've had the car over 3 years now and never had it drop this much. If it's not the battery, is there any other explanation anyone can think of? Perhaps an engine sensor failed when the battery was reconnected? The car's performance hasn't seemed to change, just the increase in fuel consumption.

Any ideas welcome

david burton · Post by **david burton** » Sat Dec 02, 2006 1:31 am

lambda (sp) sensor is usually a big culprit for mpg decrease

KITT · Post by **KITT** » Sun Dec 03, 2006 5:10 pm

How can I tell if it's the lambda sensor? Car seems to drive the same way as before. No smell of unburnt fuel either