MPG sucking more n more!

[Slaz's92Camry]

I have a 92 v6 xle 3vZ an lately my mpg has been starting to go way down. I was at about 18 mpg and now I'm at about 16/15. Any ideas as to what I should be checking to fix this?

Thanks, Slaz

[chronoti]

basic tune up stuff, then when was the last time you replaced your o2 sensors?

[Slaz's92Camry]

Should I have an o2 sensor before and after the cat? And what would happen if I don't have a cat and no check engine light on? Or is that not a problem?

[BMR]

Originally Posted by Slaz's92Camry

Should I have an o2 sensor before and after the cat?

That depends on if it's got CA emissions or not. Look under the hood, there should be a sticker telling what it's got. If it's CA, then it's got three - one in each bank's exhaust manifold, and one downstream from the cat. If no, then just the two, one in each exhaust manifold.

And what would happen if I don't have a cat and no check engine light on? Or is that not a problem?

If it's CA emissions equipped, I'm pretty sure a missing cat would trip the CEL (maybe the bulb's burnt out or someone removed it). That would cause fuel mileage to suffer a little, but not as much as you're seeing.

If it's not CA emissions, I don't think missing the cat would cause poor mileage.

[Slaz's92Camry]

Its not CA emissions. Wat else could be the cause cuz the gas prices here r killin me.

[bdy0003]

Did you check the easy stuff? Proper air pressure in the tires? Clean wires and plugs? Air filter?

[Safari Wagon]

BMR, what kind of mileage are you seeing on you 3VZ?

I am averaging about 17-18 with some towing mixed in....

[BMR]

It averages 25 MPG. 26-ish in summer, 24-ish in winter. But 95% of my miles are my 22 mile country road commute (very little stop 'n' go), which has speed limits no higher than 55; 45 most of the way. So the engine's turning like 1800 RPM in OD most of the time. Probably the best possible driving for getting high MPG. dunno if it matters, but I'm now at 5,000 ft of altitude too. Years ago when I had a 5 mile city driving commute, it got 20 MPG or thereabouts. Here's my anal-retentive gas mileage chart ever since it was new...

[Slaz's92Camry]

Tire pressure is ok but the plugs and wires may need to be changed I put them in summer of 09.
Would that cause such a decrease in mpg?

[BMR]

Man, a ton of things....

Dragging brakes
FUBAR wheel bearings
Fuel injectors
Bad O2 sensors
Coolant temperature sensor

I'd think if it were plugs or wires or something like that, it would be running like crap, but it's not?

I assume the CEL is not lit up? Does it light up when the key is first turned to the "on" position?... that is, the bulb isn't burnt out?

Or maybe it's just the normal 8% drop with winter gas?... like I see on mine???

[csaxon]

How many miles are on the engine? 02 sensors start to become inefficient around 100,000 miles.

[bdy0003]

Does the car warm up slower than usual?

[Slaz's92Camry]

Nope the warm up time is fine maybe 5/10 min when it's cold out

[Slaz's92Camry]

And CEL light isn't burnt out. Would this problem be in cahoots wit noisy lifters?

[Slaz's92Camry]

And my engine has 185k