When I hit 40 Mph, my car shakes (sort of like when you're hitting those little ridged parts of the road on interstates and what not) but when i let off the gas and press the gas again, it doesn't do it.. I'm hoping it's not my transmission, but I'm not sure. I've never messed with a transmission..

It's an automatic 2005 honda accord with 130k miles on it
i check my fluids regularly

and also when i have my AC on sometimes my car lags more than the other cars i've had and sometimes takes a minute before it speeds up while i'm pressing the gas

it feels like ..

when you're driving a manual car and you have it in a high gear at a low speed.... any suggestions?

 

You check the transmission fluid level with the car on, right? Also check the fluid color. If it is anything other than a clear red, could mean problems. Before I nuked my 700R4 tranny in my Chevy it had a real bad stuttering type feel. Fluid color also turned black/brown as the clutch packs were fried.

 

To check fluid level in a Honda Automatic, you bring the vehicle up to operating temperature, park vehicle on a level surface and shut vehicle off...then check reading on the transmission fluid dipstick. As netfreak said...check fluid condition and odor. If fluid is dark and burnt you may have a transmission issue aside from the shaking or in addition to.

As far as the shaking..check your axles, suspension, tire condition and make sure your lug nuts are tight . A lot of the shaking issues on vehicles have a lot to do with tires believe it or not! lol So start with the easiest most obvious things to check and go from there. When checking the axles move the inboard end of the axle side to side to see if there is any differential play in the transmission. Check the axle seal area for leaks. Check those items and come back and let us know what you find. Good luck!!