Struggling with these city mpg's!

[Eddie25]

im struggling to get good mpg's in this rush hour city traffic. its not really stop start stuff its more like slow highway crawl uphill home. my drive to work is awesome I seem to have the longest daily coast on this forum http://ecomodder.com/forum/showthrea...ast-31683.html
but that is too work. in the afternoon it is climbing back up the hills and im battling to get my little 1.4 below 6l per 100km (38mpg) on combined cycle. ive used all the tips on the forum but I am still struggling.

how will a problematic oxygen sensor effect this? the engine light was on for a while and a workshop diagnostic said a left bank oxygen sensor needed replacing. I borrowed a friends obd2 plug and cancelled the fault not replacing anything and now 2 months later the light has not re appeared.

however the car does not pull as well in the lower rpm as it use to it almost feels like a carb motor when its cold? could this be my problem? or is that just the figure I can expect from small engine in a quite heavy car?

[cRiPpLe_rOoStEr]

Originally Posted by Eddie25

how will a problematic oxygen sensor effect this? the engine light was on for a while and a workshop diagnostic said a left bank oxygen sensor needed replacing. I borrowed a friends obd2 plug and cancelled the fault not replacing anything and now 2 months later the light has not re appeared.

however the car does not pull as well in the lower rpm as it use to it almost feels like a carb motor when its cold? could this be my problem? or is that just the figure I can expect from small engine in a quite heavy car?

Seems like the faulty sensor is the one to blame. And if you think the 1.4L engine might be rather underpowered in the Fiesta, you have never seen the 1.0L used here in Brazil...

[Eddie25]

geez I can imagine. would be awesome for flat highway mpg tho! but that doesn't exists here and I assume neither does it that side?

[cRiPpLe_rOoStEr]

The 1.0L I'm referring to is a 4-cyl Zetec RoCam, not the current 3-cyl one. The Fiesta fitted with this engine is one of the worst cars I've ever driven.