1989 300te...sluggish...I had all systems checked, mechanic said all was ok...15 mpg. Says the O2 sensor is ok, mixture is fine. Any ideas? I would love better mpg and peppyness.
Transmission: Can I shift to 3 while driving in order to get more ummph? As long as the rpm's don't exceed their limit. Let's say I want to pass, merge, go uphill...