hard starting, but eventually starts

My 1997 Eclipse has developed a problem where it cranks a number of times before starting, except when it hasn't been run for a while like first thing in the morning. I've had it into my mechanic a number of times so far, because up until a month ago the car always started within a crank or two, hot or cold. He has replaced the fuel pump and filter and a motor control relay, but it still acts up. Also, I've noticed that the tailpipe is extremely carboned up. Could it be that the car is "flooding itself" when I shut it down, and results in a hard start when I try to restart it within a short amount of time?