Where is the sensor?? Or is the problem somewhere else? gulping petrol TOO much.

[FlatLander]

My 1AZ-FSE Avensis has been using much more petrol than it used to. Car starts fine and runs ok, but the fuel consumption has been terrible, about 12 litre per 100 km (in city driving). Usually the fuel consumption has been 9-11 litre/100 km (depending winter or summer) in city driving. i have noticed that the idle is around 1000 rpm longer than it used to ( on the start it goes to 1800 rpm, but goes down normally). It comes down to 800 rpm as soon the enginetemp (coolant temperature gauge) is in halfway. After thet the idle is "perfect", it stays steay on the 800 rpm. If i stop the engine and start it again after like 15 minutes, the idle is ones again at 1000 rpm and it comes down eventually to 800 rpm.

Could it the coolant temperature sensor thats bad (or reading wrong) or is there another sensor that informs the car that the engine is cold (but in real life its normally warm). 
Changed these parts:

- O2 sensor pre-cat (because i had a troublecode for it)

- MAF sensor (The resistance with the old one was under toyotas guidelines)

- Sparkplugs (denso)

- Airfilter 

No errorcodes now.

Im desperate with this (because im not a mecanic) problem and i´d like to fix myself, but i don´t know where start look for the broken stuff. Plus thehe garages around here are exspensive.

And the petrol prices are thro the roof here (and everywhere else too).

 

[Red_Corolla]

You say you changed your MAF, did you use a genuine Denso sensor? It's important that the MAF is genuine because aftermarket ones can be inaccurate.

I think coolant temperature is probably OK, unless you have it showing high or low on the instrument panel.

Does the engine still perform well and rev easily? Maybe an Italian tune-up is all that's required. 🙂