My dad says so, but I dunno if that's true.

 

if the O-rings are bad, yes. when the O-rings go bad unmetered air enters, the computer thinks youre running lean and adds more fuel to compensate so you run rich as hell and get bad MPG

 

How many miles does you Max have on it? Have you measured your mileage? Do you use premium fuel? Is the bad mileage in town or both highway and town?

 

regular vs premium in a 4th gen wont matter

 

Atcually it will because its high compression vq engine and it will run and give you better milage if you run premium as it is designed for premium fuel and it even says it on your gas tank.

 

I did testing a couple years back and found I average 3 mpg more on premium than on cheap gas.

 

Unmetered air will trigger a lean code, not make you run rich. There are set limits to how much adjustment of fuel delivery to obtain correct a/f as reported by the o2 until an DTC is set.

There are many variables that effect MPG. Injectors would be the last place to look on these engines. Many on here have way over 200,000 miles on original FI that get upwards of 30mpg on trips. Self included...

What is your current gas mileage?
Fill up, reset Odometer, drive until empty, fill up again, same station, do not top it off. Read the gallons on the pump and the reading on your odometer. Now comes the tricky part, you need to do MATH.

Divide the miles driven by the gallons used. Report back.