02 Chevy Malibu surges at increased speeds!?

[Olh]

Very noticeable when going up an incline/hill...or just increasing speed in general. Car rocks forward and back, RPM gauge fluctuates up and down, and noticeable loss of power. PLease dont respond with clean the air filter or some bs... an experienced mechanic would be great.

I have changed spark plugs, new spark wires, fuel filter, cleaned throttle positioning sensor.

 

[Robert M]

Check for coolant loss. Go to "dexcoolsettlement" web-site. Perhaps you are eating a bit of coolant. Hopefully, you are using a better plug than the factory units. Bosch Fusion or Denso Iridium will provide more power and better MPG's. Good luck!