I searched and came up with a few ideas, but would like more input. I'll try to be descriptive as possible.

I swapped a d16z6 vtec in my 94 cx hatch approx. 2 monthes ago. The motor was running strong for a while and now it doesn't seem to have the power during acceleration. When I start the car for the first time of the day (or after sitting for a couple hours) the motor sounds strong. It then performs like it should (normal power) for about a 1/4 mile and thats when the hesitation comes in. In mid-range rpm's, there is an obvious hesitation. The car still acclerates, but no where near as quickly as it used to. When starting the car from that point on, it sounds terrible at idle, and the motor begins to shake slightly. I'm thinking the problem is somewhere along the lines of a timing issue? Not enough fuel? The point is there is a very noticable lag in my throttle response from idle to about 3,500 rpm's...

Someone please help me out Any suggestions or ideas would be appreciated.

 

did you try adjusting your idle screw?