My wife told me the check engine light came on today in our 1998 F-150 4.6L truck.
My brother is a master mechanic on heavy equipment and he told me the O2 sensor is probably the culprit.
So my wife calls the Ford dealer here and the guy tells her there are 4 O2 sensors, 2 upstream and 2 downstream.
Is this guy way off or what?
Why would it need 4 O2 sensors?

Thanks

Mike

 

FIrst get your code read. there are thousands of codes that could have been thrown. There are 2 o2's on each side. One right after the manifold, and one after the last cat on each side.

 

Yes ,get a free reading at auto zone Mike - chances are your O2's are fine.

I have 200,000 miles on my 98 and still get fair gas mileage. That's $200 plus for all four.

When you get the codes read , don't go by what the auto zone guy tells you , sometimes they aren't accurate. write the numbers exactly as they appear on the reader - loo at it after he plugs it in.

Good Luck

 

yea look over his shoulder and let us know what it says.

 

So AutoZone will test it for free?
If it is not the O2 sensor what would you guess is causing it to come on?

 

No idea, could be anything... Yes it will be done for free.

 

I went to the Auto Zone near me and he said they can't go into the parking lot and test my vehicle it is against the law. Huh?
I called another Auto Zone and they said they recently changed their policy and no longer do diagnostic checks.
They will rent you the diagnostic tool for a $170 deposit though.

 

yup, go to autozone for the free scan.it could be anything setting that check engine light off. could be lose gas cap. o2 sensors usually last a long time assuming the car was maintained

 

Well guys when I got into the truck earlier the Check Engine light was out and it has not come back on again. Interesting!

 

For a little more assistance on your question.

I have seem O2 sensors...upstream...before cat go bad in under 50k miles
The downstream cats only tell your computer that the cats are working. They will cause an engine light...but rarely go out because of downstream exhaust temps are high enough to keep them clean.

When your check engine light comes back on, get the codes read by somebody and it will tell you exactly what's wrong. If it is an O2 sensor it will even tell which one is bad.

Even though your check engine light has gone out your computer iis still storing codes, so if you get it checked it will still tell you what was wrong.

 

Ok guys the "Check Engine" light came back on recently and I went and borrowed an OBDII from AutoZone and plugged it in.

I got this error code: P0153 HO2S Slow Response Bank 2 Sensor 1

Is this pretty easy to change?

Thanks

 

Yeah, that is an O2 specific code . That's a fairly easy one to change Mike and is the most common one that fails - driverside forward sensor - I remove the tire and inner fender well to change that one out..Makes it easy..

Good Luck

 

Thanks Jbrew.

Are the sensors from AutoZone as good as the ones from Ford or does it matter?
What kind of price are they?

Thanks

 

Global Automotive , an ebay store that sells at a good price - last time I bought Bosch (Ford OEM) I purchased 2 and they were a little over a 100 bucks (For 2) . I didn't know about Global back then. I'm not sure what the Zone charges - I think there all Bosch - Murray's, if you have that store in your area, stocks more OEM products than Auto Zone. Carquest always has the good stuff..

 

I'm dealing with a lazy O2 on the B2 forward. I swapped out the old one and the new Bosch is still not reacting properly (rapid shifts in lean-rich). I'm taking it into my mech friend and see if he can figure out what is causing the lazy reading. My mpg's arent that good and I think this is contributing to it.

On my Exp 03, 4.6, the Bank 2 sensor was very easy to change - drove the truck up on ramp, warmed the exhaust. Sprayed some PB blaster to loosen the old O2. Getting the pigtail connector is the hardest part. Could have used a really long needle nose pliers. Once disconnected, just used a box end wrench and out she came.

Carefully wiped the blaster off the port, inserted the new Bosch and tightend down. then reconnect and Voila! - still the same problem. Doh.

The psgr side (b1) was way more difficult. Had to take the tire off, take out the well liner, then wriggle my hands in there to get the old one out, and almost couldn't get the new one reconnected. What a pain. But it works perfectly!

go figure