Regarding my 1996 Cobra. My engine seems to vibrate between 1100 and 1500 rpms. When I start the car, it hangs in that range and shakes for bit, then drops down to about 900 rpms and feels smooth. At higher rpms it feels normal, not super smooth but not shakey. I've recently installed the following parts mostly because they needed replacement, I was hoping they would solve the vibration issue but haven't; -New clutch and associated parts. -New motor mounts. -New harmonic balancer. If anyone could suggest where to proceed next to solve this slight but annoying issue, it would be greatly appreciated.