I drive a 99 Honda civic. I've had the car for about 4 years, and its had its problems, but this problem is new. When I'm driving, if I let off of the accelerator, and then press on it again, my car gives one hard jerk. Not being much of a car guy, I took it to a mechanic and he said it was my throttle body that needed cleaning. This hasn't fixed the problem, so I figured I'd better ask the internet for a second opinion.

 

Auto or 5spd?

 

Vtec is just itchin to be engaged, that's all

 

This is pertinent missing info.

Also what trim level is your 99 civic (EX, DX etc)? is it a Coupe or Sedan or Hatchback?

 

There's always missing information, even if you asked for it, they respond with different answers.

 

Check your motor mounts. Sound like a possible bad front motor mount.

 

It's an automatic. EX coupe

 

engine mounts

 

My first thought is that the issue may in the transmission.

I know the previous generation automatics shift harder than I was used to, not sure if that generation automatic could have the behavior you've described but I sure would not be surprised.