Toofasgtp

So i did some test before i posted this. All my driving is 99.9% city if i get on highway it is for 5-10 miles. Driving habit has stayed the same. And i used the same gas station which has No Ethanol fuel in 87 and 91

When i got the car it had a CEL Front 02/AF sensor. I was getting around 320 miles out of a tank ( i go by when the light comes on) at that time in also which i was filling with 91.

I finally replaced the sensor (bosch) at the time i still had 1/2 tank left but was only able to get 300 miles.

I started to fill up with 87 since this car does not say premium and i did not notice a difference. Well that tank went by and WTF 275 till light

Well I ran it till 300 to get as much of the 87 out. Filled up with 91 and Again i am now getting 300 till light.

WTF is going on. Did i get a bad sensor? or is this about the norm?

Now when first got the car i seafoamed, oil then plugs before the posted issues.

Toofasgtp

O ya... since day one i have always used MMO 6-7oz per tank as a upper cylinder lube / Cleaner

decypher

After oil changes (Mobil-1 Syn. Oil + Toyota filter) I pour in a bottle of Techron fuel system cleaner before I fill up the first tank. Second tank, I run Lucas fuel injector cleaner / upper cylinder lubricant. Third tank, another bottle of Lucas; my fuel preference is 89/91/93 octane.

To save money you can buy "bottle cleaners" in larger size bottles versus the small ones.

Last time I checked I got 340+ miles out of a full tank; roughly 60% highway 40% city. Driver +1 passenger, minimal excess weight (tools, laptop bag etc.) in the trunk, cold tire pressure 29/30 psi.

dragoncoac

You need to check other components as well. How many mile on your plugs and fuel filter? Have your driving habits changed? Do you fill up at the same station to the same point when calculating mileage? I wouldn't worry about a few miles difference. Fluctuations of a few mpg's aren't a big deal.

Toofasgtp

Plugs, fuel filter pcv valve done around 4k miles ago. Last oil change just under 3k miles ago. I am doing it this weekend with pennzoil platinum. Always fill up at the same station and dont add more after the pump stops.

What is the avg i should be seeing?

Bedore

EPA MPG is 17/24.

Others report 20/29 mpg.