So here's what is new on the car:
-New spark plugs (autolite platinums gapped at 0.050")
-New upper and lower intake seals
-New PCV and upgraded hose
-New front Cat (Benchmark direct fit 49 state legal)

Raped twice for "diagnostic" by the dealer, providing no additional insight.

84k on the car, it keeps throwing the code. I'm tempted to replace the downstream front O2 sensor, but wanted to get you guys opinions first.

I originally had the P0430, replaced the cat, then had a BUNCH of misfire and rough idle codes, so I replaced the seals and plugs. Those all went away, but I'm still getting the P0430.

 

Could be a stored code. Did you clear it after you put on the new cat? Was the CEL light ever off after the repairs were completed?

It could also be a bad O2. Its not a bad idea to replace both the US and DS O2's when you replace the cat.

 

Had/havce the same problem but mine a P0420. The O2senors could also be a problem. AND the dealer will rape you, if you take it to a autovalue or other store they will do it for free. Even our local honda dealer charge 68 bucks.

 

I have a scanner and keep clearing the codes. I'll get the sensors and see if we can make this go away.

 

Quite often after installing your new plugs, the intake manifold is not seated correctly, just slightly misaligned and leaking.

Or..... you tried to use the old gaskets after changing your plugs. Did you swap in new gaskets? It is a must.

 

New upper and lower. Even cleaned the plenum of as much gunk as I could removed from it.

Called Advance and Autzone- $93 for a sensor, $57 for a universal I have to wire up. Hmmm.

 

Thats about right. When I did mine it was about $110/sensor. I think one was about $105 and the other was about $115 for the Bosch OE's.

It was worth it to me to buy the OE's. At least that way you can rule out the O2 once replaced and not worry that it may still be the problem afterward thinking "did I wire it right?"

My two cents.

 

So update....
New upstream and downstream o2 sensors, obviously the cat is new (Benchmark 49-state legal). My P0430 returned. Any ideas?

Again here is my new parts list:
-Front cat
-Front o2 sensors UP and DOWN
-spark plugs (autolite platinums for what its worth)
-upper and lower intake manifold gaskets
-gen 2 pvc hose w/ new pvc

 

I would be willing to bet your cat is pooched. I would have done that first. Can't believe the dealer didn't recommend it.

 

And the O2 sensors are all have good connections? Wiring not bad? Wiring to the ECM is okay?

 

So either my brand new cat or my brand new o2 sensors are off?

My local dealer is an a**hole and says cause they didn't install a Jag official cat it must be my fault. It was rather straight forward of a process with a direct fit replacement.

 

I get this same code when driving on the highway on cold days. It goes away by itself once the weather warms up, but it's annoying.

The dealer can possibly reprogram your car's "computer" with updated software that has looser threshold values. My guess is that the efficiency of the cat is ok, but the detection is too strict and throws P0430 even though it works within acceptable parameters. At any rate, I'm curious to see what you find.

 

Marc- What was your outcome?

 

that may be, but i have personally seen and had issue with some aftermarket cats. on a xtype i just dont recommend since theyre not fun to change especially the back 1. since it your front cat try putting a oil fouler on the bottom 02 sensor, there should be enough room. this is nothing more than a spacer that moves the sensor out more from the direct exhaust stream and less sensitive to cat inefficient codes. google it, its your cheapest easiest fix at this point

 

I bought a spacer and the damn o2 sensor doesn't fit that threading. Anyone know the lower o2 threading pitch / diameter? I'm gonna have my machinist redo the spacer threading so it works.

 

I just did this to the rear ds sensor on my car today. No threading problems. The non-foulers were part #42002 dorman "help" brand that I got at Oriely auto that are 18mm short tapered. I cleared my code (P0420) and will report back if mine worked or not. Marc, I'm surprised yours didn't fit. I can't imagine the front and rear cats would have different threads but maybe they do.

 

Well my issues is that I bought a Federal Spec cat for a Cali Spec car. There is a sticker right under the hood on the radiator support to the right of the hood latch. Read that first before buying your cat. I'm still going to try a benchmark cat, but cali spec.

 

I finnally bit the bullet and fixed my P0430. I tried the O2 sensors myself at 200.00 for the pair. I eventually took it to the shop where it was determined to be the Catalytic converter Bank 2
1 Cat 760.00
5 hrs 375.00
2 Gaskets 30.82
3 nuts 17.85
Enviro/cleaner 15.00
Tax 56.01

Total 1260.76

Believe it or not I got the dealer who I purchased the car used from over a month ago to cover the cost. I have to say i was very surprised. No cel and she is running great.