Big drop in gas mileage in the last 4-6 months

[far raf]

The engine still runs great, very quiet and no vibration, perhaps there is a slight drop in power, but I am not sure, as it drives well all around.
But I noticed that I can only make about 3/4 of what I used to on a tank of gas.
The driving style and route has not changed.

It has about 110 k miles, new air filter. I know it is time to do the plugs, and will be changing them in a month or so, but is there anything else I should check in the mean time?

[tablefor6]

How old are your tires & have you checked your tire pressure lately? I'v found that when my tires get below 35psi I see my gas mileage drop.

[far raf]

Sorry, I should have posted an update.

Found that the air filter housing was not properly closed, there was a small gap along the side closer to the engine. Once I closed that, gas mileage became much better. Then I ran a can of Seafoam through one tank of gas and it is even better now.

[chefnee]

I had something like this affect my gas mileage. Sorry again, this conversation is a little dated, but still holds true. I had a couple of issues. One was the O2 sensors and the other was a fuel tube that connects from the fuel line to the engine. My symptoms were the check-engine light. They were all leading the performance of the fuel/air mix. One of the codes say running lean and another was saying running rich. I tried with aftermarket sensors, but the codes still came back. I then ordered OEM, replaced them, and the codes went away.

The second issue had to be immediately replaced. I was getting a very heavy gasoline smell. It was very bad when I applied pressure to the throttle during driving. It turns out that the fuel tube/fuel hose that connects the gas to the engine was damaged. I order a new one and replaced it.

After both fixes, I saw an improvement average of 18~19 MPG (prior) to 23~24 MPG (after fix).