NO BENEFIT BMW E38 730i

Hello, owns a BMW E38 730i with 218 hp (built in 95) which does not produce any performance at all. The car vibrates in the stand and runs unevenly. The previous owner said it only includes the ignition times set, but that is not possible and is not true. Now I heard the salad and don’t know what was first exchanged. A mechanic typed the spark plugs once. In the error memory are only the Lambda probes, which were exchanged by the previous owner. This has made 1 hole in the exhaust and Then the problems had surfaced. Anyway, the car needs forever at 80 kmh and the consumption is the horror….