O2 sensor question

[94SRUNNER]

I installed a brand new Denso O2 sensor in my truck a few months and my gas mileage has been very inconsistent and usually less than before the install. I replace the origanal Toyota/Denso O2 sensor with a Denso O2 sensor that is intended for a Pickup with a California emissions system. I am pretty sure that this is my problem area, but I thought I would ask around first.

Also I am wondering the best way to thoroughly clean my intake plenum and throttle body. Also has any one ever cleaned out there EGR system.

If so does this help. I know that this is where that black crap comes from in the intake system.

Thanks for the help.

[V-Man]

I installed a brand new O2 sensor in my truck a few months and my gas mileage has been very inconsistent and usually less than before the install. I replace the origanal Toyota/Denso O2 sensor with a Denso O2 sensor that is intended for a Pickup with a  Cal. emissions system. I am pretty sure that this is my problem area, but I thought I would ask around first.

Also I am wondering the best way to thoroughly clean my intake plenum and throttle body. Also has any one ever cleaned out there EGR system.
If so does this help. I know that this is where that black crap comes from in the intake system.

Thanks for the help.

  I had a bad o2 sensor last summer.. I just put some lucas injector cleaner in the tank and went for a long drive..( about 6,000KM) no porblem since.. The lucas make a good way to clean the fuel/ injector ,  intake/combustion, and exhust system..  Don't forget to change your plugs.. I use the copper cheap( read un-expensive Hot ) ones in the winter to help build heat, and Platlum in the summer when I have no trouble getting the engine warmed up.   Don't worry about how much lucas to put in the tank, you can't  put too much in. I like to have a MT tank, pour the lucas in and then fill to tank, and go for a good drive.. It don't hurt to use some hi-test gas and drive it like you stole it    just don't over do it 

[94SRUNNER]

So how much will this wrong O2  sensor throw off my fuel mileage?

[94SRUNNER]

Ok, so this morning I took out the new Denso O2 sensor that I had installed a few months ago, which after a little research found that it was a  O2 sensor for a California emissions pickup. After pulling it, I inspected it and compared it to my factory O2 sensor. There was a considerable difference in the actual sensor portion which contacts the exhaust. The factory O2 sensor had a white tint to it and looked similar to what a properly running 22RE should look like. The Cali Denso O2 that I pulled out was covered in a considerable layer of black suet, like it was causing the engine to run very rich, which I am pretty sure is the main reason for the slacking fuel mileage. So for now, I reinstalled the factory O2 sensor and will monitor it to see if there is any improvement in mileage.

This brings me to my next question.  I came across a statement in one of the topics in this formum stating that Toyota will give you a new O2 sensor free of charge once your vehicle has passed the 80000 mile mark. So this morning I checked my owners manual just to see for myself and sure enough there it was on page 157 of the 1994 Owners Manual. And I quote "Oxygen Sensor-Replace the oxygen sensor when scheduled. Your Toyota dealer will make this replacement (parts and labor) at no cost to you". So has anyone had any experience with this, please pass along any information that my be relevant. For example, do I need to be the origanal owner, is this only a warranty related thing, ...etc.

Any comments or advice would be most appreciated.

Also VE3NLP I have doses my fuel with a couple of servings of the Lucas fuel treatment and while I am sure it has helped the intake system, it did not do anything noticeable to the fuel mileage. But thanks for the suggestion.

[V-Man]

Also VE3NLP I have doses my fuel with a couple of servings of the Lucas fuel treatment and while I am sure it has helped the intake system, it did not do anything noticeable to the fuel mileage. But thanks for the suggestion.

  Did you go for a nice long drive? As I said about 6,000km.

[94SRUNNER]

Yes I did do some long driving and it did not help that much. However after reinstalling the old factor sensor I notice an almost immediate improvement in fuel mileage and drivability.

[94SRUNNER]

Well I have some good news to report. I finally got fed up with my crappy gas milage and went the dealership and ordered a factory O2 sensor. I put it in last week and this past weekend I went on a big road trip. I saw gas milage numbers 29.5mpg, 33.3mpg, and about 26mpg(not solid highway miles). So if any one is questioning there O2 sensor spend the money on a factor sensor and you will notice results. I did. My highway milage before was anywhere between 21 to 24mpg, so that simple O2 change made major improvements.