16V Vibration
 

I have a 1986 16V. It has a vibration which can be felt at certain speeds and at idle. Compression is even across all cylinders. It has new engine and transmission mounts. The only thing I did recently was replace the water pump with a Laso brand and I also installed a new belt tensioner assembly . Any ideas as to what could be causing this vibration would be appreciated.
Thanks
Steif1