Its your fuel injectors. 100 miles before your next oil change, consider using a good fuel injector cleaner. I applied Berryman's B12 Chemtool to a whole tank of gas. Then I cleaned the intake valve with CRC Intake Cleaner. I'm in the same high mileage range as you.Like most modern cars my 2016 CX5 has always started quickly after cranking no more than a couple of seconds or so. However twice lately it has cranked several seconds before starting. Not a long time but noticeably longer than usual. Long enough to get your attention. Then it started and runs fine. It has 130,000 miles on it. Wondering if it needs some maintenance that I haven't done or if something is on the verge of failing. Has anyone experienced this change in behavior on their Maxda?
Result: Cranks stronger and faster than my untreated Mazda 6 with 85k miles. Also stronger acceleration and engine response.