yaris sometime stall on pullaway

[dalkill]

Hi

my wife's 2008 yaris 1.3 sedan has problem of occasionally stalling when pull away. especially when you trying to pull away quick and not slowly nurse it to get going.

When stopping it drops in revs to about 400, feel like car about to switch off and then goes up to about 500. According to other posts this is normal but feel bit low for me.
I have also noticed a slight "hunting" rev counter when i keep it a higher rev. not much but it's there.

I have cleaned the MAF sensor with MAF sensor cleaner.

Next i plan to take off the throttle body to clean with carburetor cleaner.

Then last resort the oxygen sensor. THis is the most difficult and expensive, so I really don't want to get this far.

I drive my 2000 1.3 corolla (carburetor model), and never have any issues when pulling away. I have been driving toyotas for 30 yrs now, and the only other toyota that I had this issue with was the old GLI twincam.

Any advice as to what could be the problem?

[ex-x-fire]

Sounds like weak fuel pressure. The 02 sensor doesn't have any bearing when you load the engine during acceleration. Check for vacuum leaks too.

[komichal]

Check the PCV valve and the hose for vacuum leak.
And as ex-x-fire mentioned, fuel pressure could be insufficient or maybe you just pumped in a bad batch of fuel.
Spark plugs look ok? They might be failing too and not throwing in any code (yet).