I had a similar thing with my '92 Vigor. EBay K.S. that looked like Genuine Honda (even the stamping on the metal looked good).
So, I didn't think it was bad. I scoped it before installing, but it's pretty much a microphone, and I didn't have anything else to judge it by.
Spent next several years chasing the problem (and the 2nd KS went bad in the meantime) as if it were a lean condition. I became convinced it was the wire in the loom, and even had new ones made (but not installed).
Gave in, took it to my mechanic. Of course, they're following the service manual troubleshooting flowchart, going through all the steps. I even gave them a junkyard ECM I had tried. Their 'scope showed my KS wasn't putting out enough amplititude. They bought a new one (like low $300) and fixed it, so bought another to replace the other KS, and fixed that one (but that one had obvious physical damage).
I never replaced the whips, mainly because I still saw a signal coming to the ECU on both lines. But, Google says whip replacement, particularly with another car brand, is common.
BTW, a few years before this I had a KS code, took out the EGR valve, cleaned the passage from the EGR into the intake manifold, and that fixed the code. The passage was completely clogged with spongy carbon deposits, at the I.M. I know they redesigned the passage with their V6 to catch and condense more stuff in a labrinth. I'd imagine the I4 was also redesigned. You could look into what you need to remove to check/clean the EGR passage and try that first.
It actually works a surprising percentage of times. 
