1999 lx with automatic tranny,99,000 miles. commencing at 30 mph right up to 40 mph can feel a light shuddering happening. at 40 mph i take foot off the gas pedal and let it coast back down to 30 mph and can feel and actually hear shuddering happening.feels like it,s some front end part or c/v ? also noticed while driving on a slanted roadway with right side of the road lowest the noise is slightly louder and car vibrates more. recently had wheels rotated with no new balance. also recently had new timing belt installed. is this symtomatic of bad inner c/v,s?

Let me list some condiltons with Possible sources of problems.

Noise severe under acceleration or deceleration, but OK in neutral or at a steady speed.

a. engine mounts grounding out
b. Torque converter failure
c. gear or reverse clutch failure
d. selector cable grounding out

Noise in all gears---Changes from acceleration to deceleration.

a. Transmission fluid level.
b. Front wheel driveshaft and CV joint.
c. Final drive gear set worn.

I think you are right. Most likely it is the CV joints.