ok so i just noticed something quite unnerving about the benz yesterday... she's been having some problems starting within the past few months, sounds like the starter is about to go ... well just yesterday i tried to start her after work and the starter would turn but the engine wouldn't turn over, it was like it was strugglin... so i pumped the gas and tried two more times before she started... now this doesn't happen everytime i start it up, but one time is enough for me!... what's the prognosis?

btw - starter makes normal "turn over" sound then makes a sort of grinding noise before it cranks... sometimes it makes the grinding noise then goes back to tryin to turn over...