Poor fuel economy all of a sudden

[john318isau]

I have measured my fuel economy since I bought my car in September 2004. Up until December 2005 I always averaged between low 9's l/100km and mid 10's (26 US mpg to 22, 31 UK mpg to 27). Then when the car went into a workshop they forgot to reconnect my oxygen sensor and economy suddenly dropped to 11.5 l/100km (20 US, 24 UK mpg). I found that and it returned to normal mid 9's l/100km again.

With the last fill up I got about 100km less per tank thank I usually do and averaged nearly 13 l/100km (18 US, 21 UK mpg). I haven't driven any different but this does coincide with having trouble starting the car and I also fixed all the rubber vacuum hoses. After cleaning the throttle body and airflow meter the car now starts first time but poor fuel economy remains.

Any ideas on how fuel economy can diminish so quick?

[dude8383]

maybe the cat is completely finished?

[sheepdog]

Change the fuel filter (maybe try some some injector cleaner), you may have gotten bad gas.

[m42 fan]

Yes, I was going to suggest normal tune-up type things, just to make sure it's not something simple like fuel filter, air filter, plugs, wires, and such.

Brian