Quote: Originally Posted by ven33m don't touch the idle screw. just check the fault codes mate go do some reading and go work on the car yourself... I think you really do need it... and why not touch the idle screw.. Its there for a reason... so if your sitting at a set of lights and your rev's are below 750rpm and car feels like crap what do you do? go put in light weight oil? So when you get a tune up done and your idle is not where it should be they should not touch it incase the car blows up?

Quote: Originally Posted by ven33m don't touch the idle screw. just check the fault codes Ummmmmmm What Nath said. Ive only ever had my car to a mechanic twice and both time they have ****ed my car...... And things are there to be ****ed with to make sure they are right!

In response to the original post only - If your driving around on the highway with the power button on, 'I just usually drive it in power.' and your car never hits fourth then wouldn't that be a more probable cause for high fuel consumption then the placement of your O2 sensor. Fuel economy is what is stated in the title of the original post and from reading that post i assumed you were looking for a reason as to why your car uses so much fuel. I think if your O2 sensor is working and is placed in your extractors then the high revving while in third at higher speeds is a prime suspect for high fuel consumption.