The car is an 88 760 T wagon with about 300K miles on it. There is a very prevalent engine drone that appears above about 40 mph, but that is VERY prominent when under accelleration at highway speeds, no matter how slight that accelleration may be. The tiniest change in engine speed is carried throughout the cabin...it's the noisiest car I have driven save my old air-cooled VWs. I have ruled out the driveshaft as the noise is noticibly reduced the moment I let up on the gas, and the center bearing, bushing and u-joints are good. The trans tailshaft bushing and seal are new; the transmission mount is new (I have tried the new and old styles); the engine mounts are new (the FCP Groton so-called German OEM mounts); the exhaust is relatively new (from Volvo) with no leaks, and, finally, there's nothing improper with regard to any contact between the engine/exhaust and body. Clearly I am overlooking something...any guesses? Currently my suspicion is cast upon the new engine mounts. Has anyone had any experience with these FCP Groton hydraulic mounts?

Thanks for reading!


--
Steve--88 765T, 84 764T, 87 744 (RIP), 84 242 (RIP), 52 Volkswagen, 34 Plymouth