2005 Honda Accord • 151,000 miles

My car vibrates when ac is turned on and right when I put it in gear even vibrates more?
December 18, 2012.

The Idle Air Control Valve IACV is probably bad. It keeps the idle steady when loads on the engine change. If it is not that I would suspect dirty injectors or a fuel system problem.
Try running a high quality fuel system cleaner such as BG44K. No other fuel system cleaner is going to fix issues like BG will. You will have to go to a car dealership to get it and it is $20 a bottle. I would suggest two bottles each on a full tank. You might experience some odd engine behaviour until you have ran a full third tank of gas as depsoits are being removed and it takes osme time for the computer to re-adjust things. You might check your oil after using it too because it can remove so much sludge you might need to change the oil.