At 65-70 mph the car will occaisionally vibrate. It feels like if you were to accelerate from 20 mph in 4th gear, perhaps not as prounounced. It is not dependent on engine speed or gear. The guibo has been replaced and it doesnt feel like that vibration. I can't pinpoint it. It doesn't shimmy and its not coming from the front of the car though. Nothing changes when it happens, temp, fuel consumption etc all stay the same. I notice it when i cruise between 65-70 but it doesn't happen all of the time. If i coast down to 60 it goes away and operates very smoothly just like normal. If i speed back up it may or may not back. Tranny mounts are ok, flex disk and all suspension componets are ok, brakes are fine, the wheels are properly balanced. the only thing is i have a slow leak in my left rear tire, but i always check the pressure and make sure its full. The egine idles smoothly and pulls fine and makes no noises at any RPM even during the vibration. It feels like a drive train issue. Could it be an out of balance drive shaft? if so how would that happen? As usual, any thoughts are appreciated.
Regards,
J