I bought a 1997 3.0 Ford Ranger 3 weeks ago.changed spark plugs,wires,ignition coil pak,cleaned battery terminals and new pcv valve. check engine light came on 2 days later. I have an OBD II Code Reader. Code was PO400,EGR Flow Malfuction.Put new EGR in and erased the code.Next day check engine light comes on again!Read the code ,was PO401,EGR flow insufficient detected.That was the PFE sensor.Put new one in and erased the code.A few days later check engine light comes on again!!!I read the code was PO133,O2 Sensor Circuit Slow Response (Bank 1 Sensor 1) This is the sensor before the catalitic converter,I changed it,reset the code.after 58 miles code PO133 came on again,can't believe it!!! what could be the problem? I am not an ediot when it comes to autos , but this is driving me crazy . Can anyone help me? Thanks rangercld.

 

Welcome to FTE!

Sounds like your Ranger is trying to work all the kinks out at once.

Your '97 has two "upstream" (i.e., before the cat) 02 sensors, one for each bank of cylinders. Bank 1 is the passsenger's side of the engine. Is that the sensor that was replaced?

 

No the one I replaced was on the drivers side. I guess that is bank 2.If thats the case I changed the wrong one!

 

Happens more often then you'd think. At least your truck will now have 2 new upstreams sensors, which should help it run better and improve gas mileage.

 

thank you , that o2 sensor probably what iis making my truck run a little rough.

 

I find this interesting. Will the OBD II set a different code for each of the four oxygen sensors? Looking at the sensor locations in the Technical section of this forum, it would be good to associate a particular OBD II code to each sensor so that could test/change the faulty sensor the first time. Just a thought..

Russ

 

that would make life too easy, if it isn't set up like that, never had to test it myself, so I don't know how its set up, that would be the smart thing to do.

 

The codes are indeed particular to the location of the 02 sensors. Look over codes P0131 thru P0171 and also P1128 thru P1158 and you can see how each code points to a specific sensor: OBD-II Diagnostic Trouble Codes

For example, code P0131 pertains to "HO2S-11" which is Ford-speak for "Heated Oxygen Sensor - Bank 1 (passenger side), Sensor 1 (upstream).

 

Good point about the codes. Thank you. Now all we need is a dictionary from English to Fordspeak and we will be in great shape. Guess that the Ford slang is learned with time.

:-)

Russ