Jeep Strokers

Well Crap! After nearly two months and about 1000 miles, the P0420 code came back on yesterday. Thought I had that fixed. Anyone truly have a cat go bad? I don't have an intake or exhaust leak that I can find. I'm still running stock exhaust manifold and when I put the motor together I didn't see any evidence of a crack anywhere. I believe the stock manifolds (its the two piece design not 1 piece) for the 00's and newer were supposed to fix the crack prone previous versions. Correct?

If I do have to replace the cats, I may consider putting in a header too. Any suggestions as to which ones may be better choices and which ones to avoid? I think the Borla ones are nice, but damn they're expensive.

bumping this back up the list again. Now have 3200 miles on my 4.6 and it runs great. Still got the goofy CEL P0420 code though. I cleared the last one in March and didn't have it come back on again until today. Weird that this comes every couple months. Got almost 1500 miles between this code and that last time it popped up.

Well? This has me stumped. The p0420 code is back on & it comes back on now after 30 or miles of driving after I clear it. Last thing I want to do is replace the cats & would like some suggestions as to what to check next. O2 sensors have all been replaced. No exhaust or intake leaks that I can find. I do feel the jeep is running a bit hot and lean. Plugs do show that could be the case as the insulators are all very white with no discoloration.

The motor does have 24lb injectors but would simply going to a larger injector solve a slight lean issue? I don't get any pinging. And would a lean condition be the cause for the P0420 code?

Bigger injectors would only make a difference at WOT. Not your issue.

I do know that the P0420 is a fairly generic code that could be caused by tuning issues, intake or exhaust leaks, bad injectors, timing, etc... i'm wondering if it could be the exhaust manifold. Still have the stock two piece exhaust manifold & could that be limiting flow or choking things up a bit? Would a header help it flow better and reduce exhaust temps? Therefore reducing the likelyhood of the P0420 code coming back on?

If so, do lower cost headers like JBA or Rugged Ridge work well? I have seen that these have 3/8" flanges vs the more expensive Borla or Banks that use 1/2" flanges. Does that make a real difference?

Not sure if it would be related but maybe take the cam sensor out and clean it. If the code can come on with timing maybe something is going on with it, but at least just cleaning it wouldn't cost you anything to mess with it.

cant hurt to try cleaning the cam sensor...