1. High quality ignition tune up. Plugs wires cap rotor. If you want to be bold pop a new ignition coil in too. Bosch or genuine parts only.
2. Look at flex discs
3. Try a bottle or 3 of redline fuel system cleaner. It's good stuff. If that makes no difference buy all new injectors.

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Eugene

10 E63 AMG
93 300te 4matic
07 BMW X3
14 Ford F-150 Fx2