I dont know what to tell ya. My engine does vibrate when its first started, but smooths out as it warms up. It also vibrates when the AC compresor kicks on, but all other times...relitively smooth. You may be expecting too much, but I would still try the fuel filter, or any other item that would be included in a major tune-up. According to Honda, the fuel filter is good until 150,000 miles..so I still have the original filter. From what I have been told, 4-cylinders (especially those of 6+ years ago) in general have a tendancy to vibrate. Toyota supposedly made the smoothest/questest one... but the Camry bores me, and the 4-cyl only put out 125 hp vs. 145 in the Accord. As for your power window, mine is just extremely slow (Like the motor is dying) but it has been like that since I bought the car, and has never refused to work... nor is getting any worse. Ive never had a problem with the switch. I also read that you mentioned the distributor cap and rotor, here again... I havent replaced mine yet, and wont until I have the timing belt replaced. Cap/rotor is very cheap and easy to replace.