JDM vtec

I recently swapped the engine from my 93 civic LX with a JDM 1.5L vtec D15B. It seems to run fine for the most part including getting excellent gas mileage (34mpg-city). The problem is that only around 1700-1800rpm it would shake, only at a steady speed. Most commonly I notice this in 5th gear at 40mph, not accelerating or deccelerating. Before I swapped engines, no ecu codes showed up. After #14 electronic air control valve showed. I also have not hooked up the vtec, which if anyone knows how to do this for the JDM vtec, please tell me the correct way.

Anyone know if any of these problems would be directly linked to the shaking? I dont want to have to hook up the vtec if that isnt causing it nor do i want to fix the air control valve it would not stop the shaking because it isnt causing any other problems at the moment.

I'd check your motor mounts as the first thing to do. Also, having your car at low rpm in a high gear will make your car shake.

plugin vtec how to,just scroll down a bithttp://www.honda-tech.com/zerothread?id=1171263

The mounts look fine even when it does the shaking, which i believe is still from the air control valve. However, it seems a little too expensive to test this theory since a new one costs 210. Anyone have any experience with a situation similar to this? How much would one from a junk yard run for?