oxygen sensor replacement?

[boost3dsupra]

Hi everyone,

I'm thinking of replacing the oxygen sensors on my 96 v6 camry. I dont have a cel but I'm trying to figure out things to do to improve my gas mileage. I've searched the threads and can see that replacing the oxygen sensors might do this. My car has almost 160k miles and the o2 sensors have never been replaced. I will also be doing a spark plug and spark plug wire change along with the pcv valve. I replaced my fuel filter about 30k miles ago so i dont think that needs to be changed yet. I replaced my egr valve and my engine does not drink any oil. I alway use premium and air filter is fairly clean. I think my car runs really rich sometimes when im going up hill because i can see the gas guage actually going down. I do have a obd scanner with live data capability. Is there anything I can check to see if the o2 sensors are a culprit for my lower gas mileage? Right now I'm getting about 25mpg with mostly highway driving without having a lead foot. Any advice is appreciated.

[dans01camry]

I hope your not using high octane gas as a means of improving your mileage. And if your vehicle is equiped with overdrive it needs to be off. Btw what is your RPM going up a hill?

[boost3dsupra]

i've always used premium since day 1, i just think its better. Anyways the manual recommends it and it does give the car slightly more acceleration. When going up hills i've tried everything from babying it around 1500rpm all the way to 3500rpm and every single time, i can literally see the gas guage going down. These arent huge hills either the same thing doesnt happen when i go up large hills in my neighborhood at 25 mph. But the main place where i can see this happening is from a offramp to a main road that gradually increases in height where the road is maybe 100-200ft difference from bottom to top. I take this road at around 35mph-40mph which isnt that fast either. Whats the difference with overdrive off and on? I always thought that all it does is allow the transmission to go into 4th gear or 5th gear and at slow speeds below these gears having the overdrive off or on doesnt matter. I do not have the power button on also incase anyone asks.

[ASG14]

SeaFoam the engine, that may net you 5mpg....seriously. But do it before you change the plugs. Use 1/3 of the pint bottle, and then dump the rest into the gas tank at full.

As for Premium, it;s not needed. I was running 93 untill gas prices went up, then went back to 87. I can deal with a 5hp loss for the money savings. Granted, I do have to run 91+ now due to my supercharger.

For the PCV Valve, replace the grommet as well.

As for seeing the gas guage go down, it;s from the hill and being at at angle. It;s not from using the gas. The Gen 3 gas guage can change a lot just to the angle of the car.

[ASG14]

^ No, saying use the seafoam through the brake booster. Not the crankcase itself.

[ASG14]

It;s not the same as seafoam......No one I know has done any serious damage using seafoam. I've done it in 5 diff cars myself. 5SFE, 5SFE, 1MZ-FE, 1MZ-FE, 1MZ-FE, 4AFE. I think I may have done another 1MZ as well.

[boost3dsupra]

seafoam already done many times, doesnt help. two-tone does not equal classic edition. my car is a collector's edition. It says so on the front fender. Factory label says "Collectors Edition". Well I'm still going to use premium, its the same price as regular anyways since i go to costco gas, ill pay the premium for premium haha. Can someone tell me if replacing the o2 sensor proactively will increase my gas mileage. Thats all I really want to know.

[BamZipPow]

Originally Posted by boost3dsupra

Can someone tell me if replacing the o2 sensor proactively will increase my gas mileage. Thats all I really want to know.

I guess that all depends on how it's working...

I would hook up a diagnostic program and see how well it's working. If it's skipping...then yes...replacing it would net you some improvement. If it's working fine...then no...it won't result in better gas mileage...

To proactively improve yer gas mileage...you need to start with the driver first...

[Creeps228]

Its a 13 year old car, so the efficiency of it has gone down. Also seafoaming it may help but it isnt going to get all the carbon build up out. The injectors can also be a cause; they could have carbon build-up at the nozzle or inside keeping the pintel slightly open [ im talking about a couple of mm's or thousandths of an inch ], causing the fuel pump to pump more gas to maintain a steady fuel rail pressure since it could be leaking small amount of gas into the cylinder after TDC on the power stroke, so drop some seafoam in the gas tank, and after that tank has finished add a bottle of injector cleaner to your next fill up just to help them keep them clean a bit. And also who ever said to keep OD off, is completely nuts, OD helps maintain lower RPM at high speeds aka less fuel being used. Now when you said the gas guage geos dwon on incline, thats normal because i believe, correct me if im wrong, the guage is connected to some fuel level device, which floats above the gasoline in the tank. So when the car goes up a hill the gas is then at the back of the tank because thats just how the world works, so the flue float level thing is at the front of the tank reading less fuel than there actually is because most of it is at the back of the gas tank.

PS: If you havent gotten an O2 sensor code fro either banks, dont even bother changing them. Your OBD1 scanner tool should be giving you voltage readings near the specs of your car, and if it is, the O2 sensors are doing their job.

[FireFire]

check the engine temp sensor. I just did that and my o2 havn't been replaced. Mine is 320K Km and with winter tire and canadian winter gas, I got 9.4L/100km.

Someone at this forum said never replace the O2 if the CEL not on.