2000 Corolla LE Poor Fuel Economy ?-Testing Upstream O2 Sensor-?

[cj10566]

So I recently purchase a 2000 Corolla LE Auto with 96k on it and it only gets about 25 MPG which from what I read is on the lower end for a corolla.

The car runs fine and seems to not have any issues at all.
I live in NY and commute about 30+ miles a day highway.
I have been driving it lightly with no heavy foot trying to see if it's my driving and I really doubt it is.
I've also driven a 2009 Corolla with 70k and had no regard for how I was driving and it was getting over 31+ MPG (I know it's a newer car, but I've read all over that older corolla would get better MPG then newer ones).
I also put some fuel injector cleaner in today and unplug the ECU fuse for 30 seconds to reset.

The owner before me provide all receipts from dealer for work done and parts replaced. I was also able to verify the receipts with the dealer to confirm I know overboard but I did.

Here is the list of everything done in the last 10k miles by the previous owner

-Catalytic Converter
-EVAP Canister
-4 New Tires (I've check tire PSI/condition etc.)
-Alignment
-Downstream O2 Sensor
-MAF Sensor
-Power Steering Pump
-V-Ribbed Belt
-Toyota Battery

Any ideas?

I was thinking from reading a lot of post online that maybe the upstream O2 sensor is starting to get sluggish but not pop CEL and considering the previous work done.
A few people say that replacing the upstream sensor has given them back good fuel economy and they had similar issue.
Does anyone know the specs and steps for testing the upstream O2 sensor?

Thanks for any help...

 

[hugho]

TIPS: !. check for codes. If none new plugs,air filter, egt, and cleaning the maf sensor, o2 sensors etc as well as putting in on a good engine OBD2 analyzer. There is a filter in the VVT system that plugs up sometimes. auto matics should be getting 35 or so in that yr.

 

[TomDee]

VTV ? Vac transmit Valve ?? Is the VVT filter this type valve VTV with a lil rubber insert on it looks filled W cotton or such or is it different? Ive dreaded po4020 or W/e Ive to look but its Dwnstrm sensor replaced W new 1 Hour lite returns WTF Cat is fine Full flow My MPG at 75 ish is still 42-460 a tank full depending How long I like fuel lite on ??? To pass NC inspection I turn off lite take to my friend at insp station run thru fast I lv my scanner rt on drvr floor

 

[TomDee]

mines Auto too