My 94 C280 has a harder time starting when the car is warmed up rather than
cold. In the morning it starts up fine. If the car is recently driven and
the engine is slightly warm, it would take a harder time to start the car, i
would have to step on the accelerator to start it up. I have replaced the
spark plugs, and thought maybe i should also replace the cap and
rotor......but discover they dont use one (or atleast the catalog dont list
any cap and rotor parts for this model year). Any help? Anyone have any idea
of what the problem might be? anyone had a similar problem?

I have seen coolant sensors fail and I have seen fuel injectors fail and leak into the cylinders.

If the injectors are leaking will it be smelling fuel?, becuase i try looking looking/smelling to see if there are any leaks, but everything seems to be ok. As for the coolant sensor...is this the one that goes to the computer?

Thanks for the response.

I have a 1995 C280. My car did the same thing. Started fine when cold, but wouldn't usually start when warm. Always take a couple turns of the ignition before it finally started. Is your engine still turning when you do this?
Then your problem is the Overvolt Protection Relay. I am 95% sure that will cure your problem. This is a VERY VERY common problem. The new ones have been upgraded to fix this problem. You can get them right here on partsshop or fastlane. Good luck and be sure to let us know how it goes!