I have a '96 Taurus with 106,000 miles. Code P0430 just popped up, and car idles rough sometimes.
From what I understand the P0430 code means the cat isn't functioning properly, or bad o2 sensor, or exhaust leak. ?
I recently noticed the cam syncro making a chirping noise (i changed the cam sensor about 10k ago) I also suspect the head gasket maybe leaking. (had to add coolant a couple times and heater doesn't blow hot)
This may sound stupid (I'm a Noob) but could either of those issues cause the P0430 Code?
It means the catalytic convertor isn't working as well as it should be. Sometimes changing the upstream O2 sensor will make this code go away (if the old sensor was switching too slowly), but most of the time it means you have to replace the catalytic convertor.
If the cam sensor is chirping, the part is probably bad again. Did you use a cheap replacement part (Dorman or Cardone)? Make sure you use a Motorcraft cam syncro.
Coolant being burned from a leaking head gasket can foul a catalytic convertor and cause a P0430 code.
You should investigate and solve the leaking head gasket and/or misfire before replacing the catalytic convertors.
Oh, you just changed the sensor. To fix the chirping you have to replace the whole synchronizer shaft and the sensor (puck) if it looks damaged. Just changing the sensor doesn't fix the problem as you found out.
Take it from someone who spent 700 bucks on the car and still has to replace the cats. Don't mess around replacing things you "think" may trigger the code. I replaced the IAC, UIM gaskets, TB gasket, MAF Sensor, both Upstream o2 sensors, and so on. Still have the code, if your head gasket is leaking then get it changed, coolant and unburned fuel will eat the cats up quick.