I was having this problem and I believe I have found a fix for it. I joined another forum group called ECOMODDER, these guy's are really into the VX lean burn civics. I found through them that one very important thing to do is make sure that the exhaust manifold is well grounded!! This 5 wire O2 sensor is very sensitive to good ground!! I made a ground strap out of copper braided strap that connects the manifold directly to the nearby body ground that comes off the front of the head. I also cleaned and de-rusted all of the contact points including the area under the O2 sensor. Since doing this I've been able to get the car to pass Ca. Smog test and it now runs great, no hesitation or any other problems.

 

Yeah I've been lurking around on ecomodder too, along with gassavers.
hmm, I have been thinking of cleaning all the grounds in the engine bay since some of them really look corroded. Cleaning the threads around the o2 sensor and putting that extra ground is a good idea though. thanks for the input, I'll post what I find.

 

That's a great tip. Makes sense that the typically rusty manifold can lose its ground. I wouldn't have thought of checking that.

 

Let me know how it turns out. thanks

 

One other thing I realized when I replaced the blown head gasket that the original exhaust manifold gasket was a steel gasket. The one that replaced it was a fiber composition thus reducing the ground path to the manifold. That's why I added the ground strap directly to the manifold.

 

this is why i love this forum.....im gonna do that just in case.you can never have enough grounding.it affects soo much.