Hard starting

Hard starting sometimes, never know when until I turn the key over. Sometimes it starts up with no problem, other times it turns over like its not firing or getting fuel, but it will eventually start if I hold the key over and gas pedal all the way down. Once started runs fine at idle, will throttle up fine. When I put it in gear will run find until I take my foot off the brake give it gas, then it spits and sputters and will not go, other time it takes off fine like there's no problem. It is not consistent when I have this problem, it may run fine 2 out of 3 times, then give me problems the next time I try to start it.