2009 toyota avalon car runs fine, put in gear car still runs fine. When i turn the air conditioning the engine it self begins to intermittently jerk from front to back and also does so when i drive

Sounds like it needs a full tune up, and check motor/trans mounts.

thanks for the detail dude. just had a tune up not sure what you mean maybe you could be more specific and maybe answer my question about the air conditioning too?

also, i understand the mount part but why is it only moving when the a/c is on? and it's not shaking it moves just as it would when you put the car in gear, but it does it sparatically

You could be misfiring and is noticeable under load from the A/C. The A/C is suppose to turn off and on but doing so too many intervals is an issue that is a sign of to low on R34 may have a leak or pump is no good. Also pump can be the bad and lock up or hard to rotate for the engine at this moment and is trying to overcome the strain or there is a misfire, Could be bad spark plug, plug wire or fuel injector or low compression, and could also be a mount bad or is not good for the mounts and can damage them. Could be a wire connector loose or plug wires arching on the motor or each other. If you know the A/C was recently filled up then have it checked for low level and leaks. If it passes with no leaks then your at the A/C shop get them to check the rest of the system. A new pump may be what you need. If so, t that point its time to take big Gulp.