Infiniti,Why does my car struggle to start every 4th to 5th time?

Car struggles "chugs" to start about every 4th-5th start-up. When it chugs it sounds/feels like there's no compression, no power. I replaced the battery, it started perfect like 7 times in a row, then it started the same bad-cycling starts. It's like a computer glitch, because when it chugs, I turn if off, wait 30 seconds and re-start… it chugs some but not as bad and starts up (it's never not started). If I have a bad start-up, once I get it re-started, I usually drive home… park it overnight… next day, it fires right up with no issue.

So what do you think i