It's not related to the cat. I have a test pipe and I think blackfox has one as well.
So far, it's not the coils, the sparkplugs, the airfilter is new, the IACV, the TPS, the crank position sensor near the alternator, valve adjustment, EVAP/Charcoal canisters, the cams align properly and show no significant wear, I've run redline fuel system cleaner, the vacuum seems ok
We worked on the car like 10 hours and nothing. This is getting really really frustrating.

 

The strange part is the P0170 and P0172 CEL I get after some idling. It means system too rich, and that's how it feels and sounds... but the spark plugs look normal, maybe a tad on the lean side.

 

After all that it makes me think about fuel pressure issue maybe... or the fuel pump could possible be starting to go bad.

Like you I have tried it all. Am going to also clean out the TB and Intake manifold as there seems to be a lot of build up inside.

 

So I have a feeling some of my issues may actually be due to my CAt and O2. Pulled the O2 out today and I saw the....



The comb inside the CAT is shifting back and forth. I was actually able to put a finger through the O2 sensor hole and move the comb back towards the motor side. Upon further inspection it looks as though it may have also melted some.

I believe this is blocking my engines ability to run properly, and this is causing my strange hesitation at low and sometimes throughout the rpm range. Car feels almost held back like it's being robbed of power.

8yr/80K mile warranty on the CAT. Luckily for me I'm year 7 and at 63K miles. Will be taking it to dealer to have it covered. Though I'll be sourcing the O2 on my own(dealer o2 quote is wtf!)

 

Please report back any changes after you replace the cat.

 

Dealer replaced CAT and O2 under warranty. I haven't had a chance to drive it to much, but the initial drive home felt good. I'll do a longer drive today to allow the motor to really warm up as the problems seem to happen after driving for some time, but otherwise so far so good.

 

Looking forward to hearing if your problem is fixed. If it looks like your issue has been resolved, I'm going to pull my cat off and check it out.

 

Any news HvRRZ? I still believe my IACV may be culprit. I disassembled it per Billman's instructions. I was able to spin the shaft 180 degrees, and I found some gunk that had stuck to the back. I think it still might need some cleaning, though. The shaft will spin 360 degrees easily by hand, but it still has some very light dragging in some spots.

I'm going to go over these things tonight:

- Recheck valve adjustment w/ new VA tool
- Thoroughly clean IACV
- Change Oil
- Check catalytic converter

 

Does the 06+ have an IACV??

Apologies for the long wait on my update. The car feels good daily driving after the CAT and O2 change. I can drive aggressive and the power feels smooth. The shacky feeling is still a bit there at idle, but I have realized something.... the real issues seem to start up soon as I engage VTEC. Before then the symptoms are minimal, but once I get on the high and get through a few gears... After is when I begun to feel the hesitation in power. Such a headache!!

 

I'm starting to think about possible pulling the tranny and checking the clutch system. Now to just find some time!