Chrysler Repair: 2001 crystler 300m takes awhile to crank, crystler, miss fire

Question
my car takes 3 to 4 seconds to crank after turning to the on position.  I have to hold the key in the "on" positions for seconds before it will crank.  I have had the lights on the dash flicker on and off. The engine light has been on for months. I have had diagnostic readings from the crystler dealer that only shows a "multiple misfire" code.  I have had the gas line cleaned ($157.00)  I have had the coil pack and plugs changed ($297.00).  I have had a so-called engine cleaner ($100.00).  But nothing seems to work and no one can tell me what the problem is.

Answer
next time u start it up  cycle the key 3 times  but don't start it up. On the 4th time go all the way and start it up  if u fire right up then u have a fuel pump that is not holding prime and will need a new one. As for the miss fire do u feel it miss?  I live in ATlanta