Triton 4.6L, 99 Ford F150, 125+ miles.
Engine light is on, scanner says PO420 (Bank 1).
Just changed plugs...they were real bad. Truck now RUNS fine, but light is on (had reset earlier with reader, and then of course when changing plugs I disconnected the batter).
SO, I am GUESSING from the code that the best option is to replace the per-cat O2 sensor on the passenger side. Forum searches show HOW, even tho some having difficulty getting the old one out of the exhaust pipe.
What I am looking for (I THINK that sensor is O2S11, but not sure), is the best place to purchase one (for the least price). Checked PartsGeeks--none available, but in my search, I am not finding "O2S11", so really don't know which one to purchase.
Any guidance on the idea that this particular sensor might be causing the light issue, as well as a part number/identifier for a replacement, AND a good site to check for price(s)?

 

I have always used bosch with no problems. Bank 1 which sensor 1 or 2.

 

I've also used Bosch with no probs. check rockauto they usually have good prices and fast delv.

 

None, you don't need an O2 sensor, they're working as they should and the DTC tells exactly what the problem is.

 

[MENTION=113]Jbrew[/MENTION]....The ONLY code given by the ODB reader was 420 (Bank 1). Not sure what DTC is....so, what IS my issue?

 

P0420 is a catalytic converter code front cat has gone bad there are four so I'd replace both front cats and call it a day

 

Yea, just keep in mind,- faulty HO2S sensors do not produce the DTCs (DiagnosticTroubleCodes) P0420 and P0430. The sensors must all be tested and shown to be reliable before the Catalyst Monitor can be called by the Executive.

The most common cause is a downstream converter crack. They crack all the way across the bottom under the heat-shield.

A leak in the manifold or Y section.

Cats are plugging up. They will begin to heat up and even glow in the dark when they get real bad.

You may squeak through the emissions test with two failing catalysts, although performance of the engine will be poor - running smoothly but well down on power.

Converters are free if you go about it a certain way.

 

[MENTION=113]Jbrew[/MENTION]...thanks for the great class. Guess I need to bring it to a shop to check for leaks...I visually inspected the converters and manifold and didn't SEE anything that looked like cracks/holes etc. Would a muffler shop, like Midas, be a bit cheaper than a Ford Dealer (in general)?

 

Hard to say. If you haven't any noticeable leaks, then it's most likley not the problem. Leaks are very easy to determine w/shop vac,leaf blower or air compressor. You just position the whatnot into the tailpipe (COLD) and turn whatever your useing on. Grab a squirt bottle w/soapy water and find every little leak in the system quickly.

They usually leak at the rear of bank ones (passenger side)manifold bolts. The transmission mount gets bad, trans drops about 3/4" and eventually snaps the manifold bolts.

If your going to farm the work out, keep in mind that your existing converters are worth 160-200 bucks, - as long as they weren't gutted. So you should get a good price from an exhaust shop if you end up having to swap those out.

How is it running?

What spark plugs did you use?

 

Running good....Replaced with original Platinum (autocraft, I THINK)....just last weekend. (BUT, light was on before then).