2005 Maxima SE Auto Trans, 195,000 KMS / 121,000 MILES

Lately just this past month I've noticed that there is a very slight delay when I turn the key where the engine hesitates like its clogged/dirty or something.
About 1-2 seconds at most. But its 1-2 seconds more than usual. Used to have an instant start up no issues.

Things I've done recently to rule out or consider:
- Recently I ran Redline SL-1 (about 3 tanks or so ago) through the system and killed one of my Air Fuel ratio (o2) sensors (by the firewall) and I replaced that one a couple weeks ago.
- All My other Oxygen sensors / Air Fuel ratio sensors are less than a year old. NTK.
- No check engine light or pending codes in the system.
- Less than 1 year old OEM battery and a negative battery cable.
- 1 year old aftermarket alternator/starter
- Replaced PCV Valve a while ago.
- New OEM throttle body - replaced about 2 years ago
- My entire exhaust system except the mufflers is also new less than a year old.
- Air filter about a year ago (FRAM tough guard)
- Synthetic Mobil 1 5w30 High Mileage oil changed every 5000km/3000miles. Oil changed 2 weeks ago or so. Purolator Pureone oil filter.
- OEM front and rear motor engine mounts done a year ago. I still have to do the tranny and other side mount though. Some clunking when I accelerate from a stop too fast lol probably tranny mount.
- I always run Shell Premium V-Power gasoline. 91

I do mostly daily highway driving, not many short trips. I also drive 130-160KMPH / 80-100 MPH speed wise an hour daily haha.

Maybeee... Crankshaft position sensor on its way out? Camshaft position sensor on its way out?

Any thoughts on what this could be?
Thanks everyone!