i have a 1997 honda civic dx coupe. I have replaced all bushings in car with urthane bushings. it has adj. coil overs, adj. kyb shocks. racing conrols arms, adj. caster/camber plates, all strut tower braces upper and lower, lower "H" brace/ engine cradle. It has a rebuilt transmission with ACT lightened fly wheel, and stock clutch. I have had an alignment and all tires balanced and rotated. I still have a really bad vibration. You don't really notice it until you are on the interstate and running about 65 to 70 mph. If you get in the throttle hard the vibration becomes more pronounced. Anything over 70 mph and it gets worse, as you let off the throttle it decreases but comes back as soon as you get in the gas. I have also replace all motor mounts with urthane replacements. Any ideas as to what the hell is going on with my car.

 

What shape are your CV axles in?

 

Yeah its probably your cv axles, or even cheap coil overs would do that.