The engine vibration is most noticeable when in idle and in drive though it is still present when in neutral. Mechanical loads like the AC seemed to be making it worse but I noticed that with the AC off, though the vibration was lessened that other things would cause the vibration to get worse, like electrical loads. Turn on the headlights, run the windshield wipers, even using the power windows would cause the vibration to get as bad as when the AC was on. Once driving and reaching 1000 rpm or so the engine vibration either stopped or was no longer noticeable and the car drives fine. This first started after going to a Jiffy Lube and getting the oil changed and tires rotated and also getting the air filter replaced. The Mazda dealer checked the car out for vacuum leaks and found none and was not able to determine what the problem was. I replaced all 5 motor mounts because 3 were worn but that didn't make any difference. Two other service shops have failed to find the problem. Options?
My car has 87000 miles.
My car has an automatic transmission.
The engine vibration will need to be checked to see if it is worse in drive than it is in reverse. If the vibration is less apparent in reverse, then the motor mounts will need to be neutralized to center the motor mounts. If the vibration is even when the engine is in neutral, then the engine crankshaft damper is bad and causing the engine vibration. I recommend having a certified mechanic, such as one from YourMechanic, check to see if the motor mounts or the engine damper is at fault. They will be able to diagnose your engine vibration and ensure that the correct repairs are made on your vehicle.