1995 626 2.0L - Had all of my motor mounts replaced, cleaned MAF and throttle body. Finally figured out it was due to a bad exhaust valve on cylinder #3. Had a shop do a compression test and sure enough got 40% compression loss. Leak down test pinpointed the culprit to cylinder 3 exhaust valve. The reason the car was shaking so badly was due a cylinder not performing well and causing an imbalance. If your car looks and sounds like what mine does in this video get a compression and leak down test done! It only cost me $86 for both tests and now after 7 years I finally know what is causing the vibration. Yes, I drove the car like this for 7 years (very light use though). It started out like a kitten purring and I kind of liked it. Then over the years it goes worse as the cylinder lost more and more compression (which now I know why). Horrible gas mileage, vibration, shaking, and feels like the car has 1/2 the power it used to. For the longest time I thought I had a gasoline leak because I'd chew right through a whole tank of gas in a matter of days. Getting about 15-17mpg with very light use. Can't even explain how much better I feel at least knowing what's wrong with the car. You can't fix it unless you know what's wrong! Now I know and working towards fixing her. Glad I got video of the whole ordeal so that it might save you the time and frustration it cost me over the course of many years.
mazda, 626, heavy, vibration, rough, idle, shake, shaking