vibration @ 1,700 rpms
 

I own a 94 Mustang GT with a 5 speed transmission. Through first, second, and sometimes third gear I hear a loud vibration from the rear of the motor near the flywheel at 1,700 rpms. It doesnt sound like anything that could be damaging to the engine, but its rather annoying. After the car has been driven for a little while the vibration goes away. Im wondering if theres just a bolt loose on the cover that surrounds the flywheel. Any feedback would be appreciated.

Does the vibration/noise change when you press the clutch pedal? I would possibly suspect the throwout bearing.

Check the heat shields on your cats, too.

Take care,
~Chris

The vibration sound doesnt change when i press my clutch but goes away completely. Its only noticable when the motor is turning 1,700 rpms or near that. Thanx for the advice guys, Ill look into both possibilities.

exhaust leak
 

My buddy and I were trying to figure out why my Flowmasters were sounding so quiet today and we discovered a leak in the exhaust near the front catalytic converter on the passengers side. Im anticipating this to be the vibration Im hearing... Probably some exhaust pressure causing the heat shield to rattle as you suggested PKRWUD. Thanks for the help guys, Ill keep you posted on the turnout.

While you are down there, take a look at the trans/ and motor mounts. I recently had a vibration at 2k with my foot off the gas, and soon, my transmission was practically jumping through the floor.