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97 explorer help

Hi guys, Did an OBD 2 scan of my 97 Ford Explorer v8 5.0L. It came back with the following codes. PO304 ---------cylinder 4 misfire PO153 ----------O2 circuit slow response bank 2 sensor 1 PO133 ---------- O2 circuit slow response bank 1 sensor 1 PO171 ----------System to lean

I am looking for a couple of pieces of information that maybe different people may have experience with.

  1. Do all these put together indicate one problem or multiple problems that need to be addressed

2.The O2 sensor has not been replaced since I have owned the truck in

2000 so I imagine that outside the misfire on cylinder 4 these are overdue for replacement.

A) Are the O2 sensors the same in all locations or are they different types, (i.e. can I order 2 of the same or are their differences between the O2 sensors located in different locations of the truck.

B) Anyone knows a website with pictures of the locations of these sensors, or can describe these locations.

Any advice or how to's is greatly appreciated.

Reply to
dsd91
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Generally speaking, address the first code that comes up first; solving the first will often clear (some of) the others.

Reply to
Sharon Cooke

This looks like 2 separate issues: -#4 cylinder misfire -Vacuum leak It is possible that the system is leaning out the mixture to compensate for the dead cylinder, but I believe the lean code would only be for the affected cylinder bank. Your Explorer will have 4 Oxygen Sensors. One in front of each catalytic converter and one after each converter. The downstream sensors are Catalyst Efficiency monitors and do not have anything to do with the Air-Fuel mixture. The chance of both upstream O2 sensors failing is pretty slim, they just don't fail as often as many folks believe unless they are contaminated for some reason. I would suggest that you address the misfire, clear the codes and drive the vehicle. If the lean codes return start looking for a vacuum leak. (Of course, keep a lookout for obvious leaks while fixing the misfire).

Reply to
Tom Adkins

Is there a a very obvious place to start looking for vacum leaks? I remember I did have that problem a year ago and a machanic fixed it. Are most of these vacum hoses on top under the hood or underneth the engine from below.

Reply to
dsd91

The obvious places are vacuum lines on or around the top of the engine. Many

5.0s had a vacuum line under the upper plenum that was prone to leaking. This was on older 5.0L engines, so I'm not sure about your Explorer. If you look at the emissions sticker, I believe it should have a vacuum diagram showing the relative location of components.
Reply to
Tom Adkins

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