I have a 97 F-150 Supercab, 4.6L (W). This past weekend the CEL came on and when I pulled the code it was P0430. I have replaced the spark plugs, PVC, spark plug wires, checked the cats, replaced the EGR valve and sensor, cleaned clogged EGR ports, replaced the fuel filter, checked the connections to my fuel injectors, and removed/inspected/cleaned the and throttle body...I still have this code. I do not think it is the O2 sensor but I am open to suggestions....please help.

 

Welcome to FTE ascaife! What leads you to not suspect the O2 sensor on bank 2?

 

I notice my engine is running rough in idle, min speed, and high speed. Not a bad run but feels like it is missing...that is what led me to the spark plugs, wires, etc...

 

P0430 = Catalyst System Efficiency Below Threshold (Bank 2). The first thing to check is the rear O2 sensor and wiring. Also check the wiring at the PCM for damage, loose pins, damaged pins or corrosion. Good luck!

 

If you have a P0420 or P0430 code, it means that the rear O2 sensor is detecting too much oxygen and that the waveform of the O2 sensor is too active, indicating a failed catalytic converter. What have you checked on the converter, because on modern vehicle, they rarely plug up, break apart, or do any of the oldschool stuff. They converter is monitored by its ability to absorb and use up free oxygen by combining it with unburned fuel. If the rear O2 sensor is damaged in any way, its signal output will not be the same as a bad converter, you will instead get an O2 sensor code.

So sorry to break it to you, but you've got a bad catalytic converter. That code is only ever wrong if you have an exhaust leak. I think you have another problem that caused these converters to fail, a problem you need to get fixed before replacing the converter, otherwise the new converters will be damaged as well. You need to find someone with a scanner (not a code reader) who can look at the freeze frame data and check the long term fuel trim. That can help diagnose what the other problem is and correct it, even if there are no other codes. if it feels rough at idle, I would suspect a vacuum leak or MAF sensor to be the cause of that, especially with what you've already done. I wouldn't rule out a bad coil pack.

 

Thanks for the advice...I will seek out someone with a scanner because the only code I am receiving is the P0430.

 

Great inof!
I have a 2006 Explorer Limited 4.6 and watched the video. This is exactly what my OB2 tool (bluetooth ScanTool and Torque Pro) show for bank 2. Ban k 1 is good (upstream O2 oscillates and downstream is flat) and both Bank 2 O2's oscillate.

I guess the next question- what causes a cat to fail? Time? another component (IE: tune up, intake lead, etc.)??

 

The 420/430 code is the CAT monitors for each bank.
The rear sensor is normally not changing it's out put very much from sensing a steady 'good' exhaust gas output from the cat ahead of it.
The computer looks at the 'Ratio' of switching between them as the way they monitor the Cat health.
When the rear begins to switch by following the front and goes out of ratio limits the code is set for that bank.
Use a Scanner to look at the rear sensor output for excessive activity.
Compare both sides.
If you only have a 430, the other side should not be seen as moving it output nearly as much unless that cat is getting more inactive.
.
If the truck was ever driven with multiple misfires, that could have damaged the cats and even caused them to melt from burning fuel in them and cause exhaust restriction to the point the motor power is reduced.
Do the testing carefully and make the judgement.
Good luck.

 

Double check the plugs are tight. A loose plug can cause low loss of compression and give those symptoms. That's what the issue was with mine a loose plug. Someone used the anti seize crap on the plugs and they loosened with vibration of the motor.