engine vibration.

I am having a vibration problem with my '89 mustang lx. It vibrates bad between 1000 and 1500 rpms. Above 1500 it is better and below 1000 it is better. I have already elimated ignition, fuel delivery, compression and vacuum leaks. I'm thinking either harmonic balancer, torque converter, or flex plate. I was just wodering if anyone has had a similar problem.

I had the same problem in my '95 5.0 GT. Bad vibration around 1000 rpm's then smoothed out 1500 to 2000. It turned out that the harmonic balancer went bad. Check it quickly it can do a lot of damage to your main bearings and rear main seal. It damage my rear main seal. Luckily I caught it soon enough to not cause any other damage. Good luck.