So...anybody have any bad experiences with Bosch oxygen sensors? I replaced my pre-cat like...3 years ago. Anyway, I've already replaced my MAP sensor thinking it would fix my long drive MPG drop. It did improve, but only on short drives. So I got my hands on a scan tool, and I went about 160 miles to Normal, IL to visit a friend. So as I was driving, I took a quick look at everything and see if there is a difference in readings...

Basically, my problem is I get a check engine light with P0171 lean system when driving on the highway for a long period of time. There's a strong stench of gas, growly tone, very hard shifts when I get back to city driving...it's just pretty rough. According to the scan tool, my pre-cat o2 sensor sends a consistent voltage of .06V. I let the truck sit for a while to cool off, and I checked the scan tool again, and it initially stayed at about .9V, but then it started fluctuations as low as .04V to 1V.

So...at 3 years old, do these Bosch things really suck that bad? I really can't come up with any other solutions of what could cause this problem after driving a long time. Good thing it was only 160 miles, because the first quarter tank is high gas mileage, but then it starts dropping little by little, so most of the drive was when it was running healthy.

 

I got the same code a few days ago, and my pre cat bosch went out after 5 months! So, maybe I just got a bad one of the batch, I dont know, but I may be looking for a different brand this time around.

 

I hate anything bosch with a passion.. My dad on his Ranger has replaced his upstream right bank O2 Sensor (Under warranty) 3 times now... I keep telling him to go buy a dealer sensor.

There are just some parts I'd rather get from the dealer.. this is one of them.. but thats just me..

Denso or Densco.. i forget the spelling is a good brand.

 

Ah, okay, so the Bosch really aren't that dependable. I wish I knew what readings the oxygen sensors are supposed to give in my type of setting so I am completely sure of dumping money into it.

As far as I know, the original is Denso.

 

I just replaced my upstream O2 with a Bosch a new throttle position sensor and a new intake oxygen temp sensor all at one time so I can’t say which one made the difference but my 2.5L runs much better now very smooth and responsive great idling now also. Everything I have read on this forum says the Bosch are the best O2 that is why I got it.

 

Yea, I've been hearing good and bad. I'll look into reviews more and such. I dunno....maybe this is a good excuse to get wideband. I definitely should monitor with the scan tool more often this week.

 

I use an Android app and a Bluetooth adapter to monitor my two o2 sensors. I'm running two brand new Denso's pre and post cat.

At idle with a fully warmed up engine the narrow band pre-cat o2 should cycle between .1v and .9v. At a steady cruise of 45 - 55 mph again it should cycle between .1v and .9v. When taking off you should see the pre-cat o2 sensor go up to around .7v to .9v solid as you accelerate. However, I'm finding with my truck that at 75mph my pre-cat o2 is cycling between .7v and .9v and my post cat o2 is staying at .2v. And I'm not quite sure that's right. It seems high and could be the reason for my crappy highway mileage. My in town gas mileage is better than my highway mileage which is weird.

I just replaced my entire exhaust system yesterday with Edelbrock headers and y-pipe and then 3" mandrel all the way back but I haven't done any testing of the o2's yet to see if that made any difference.

Anyway, I'm with you, I may get a wideband. They are just so much more accurate.

 

Like my dad always said Sensors are one thing you dont cheap out on; he only did because he has been out of work for some time due to strokes.

 

As I have seen most brand names now have the same product as the no name company’s they only charge those high prices still with the fancy brand name.

It’s a guessing game now what was reliable two years ago may be made in China like the cheap stuff.

So that old saying is out the window don’t count on the old names for quality it may be an illusion of quality only at a high price.

 

Your Def. Right about that one.. Like Rockford Fosgate; use to all be made in the USA now its China like everything else.. and I can tell you the quality is just not there..