2010 Ram 4.7l. No crank?

P0300 is random/multi cylinder misfire. So you had more than one cylinder misfiring. Replacing the spark plugs and coils was a good idea, especially if the truck has never been tuned up and has over 100,000 miles on it. There are several causes, other than ignition for a P0300. Mass airflow sensor, for example. Since you disconnected the battery, if you didn't use a memory saver device, the security system, if equipped, may have been enabled and the vehicle is now locked down. If this is the case you're going back to the Dealer for a reflash (reprogramming) of the computers. Jim

The 10 second run then quit is a typical security symptom. Plus you caused yourself more problems by disconnecting main power without using the memory saver tool. So a tow to the dealer is what you need now.

The truck only has 84,000 miles. And no security system. I've disconnected the battery B4 and had no issues. I failed to mention that I do get one code. The code for the mass air flow, because it is unplugged because I have the throttle body cover removed. That wouldn't cause it just to click and not even spin over.

2010, it’s got a security system.

Hmmmmmm, I don't know about that. With that throttle body cover off it might not crank. A friend had a 2000 Blazer that wouldn't run with the throttle body cover off. Different vehicle, I know, but it could be a similar set up. Put the cover and everything back together and see what happens. That Blazer had us scratching our heads for a little bit. Jim

This truck DOES NOT have a security system. And as far as the cover being off, it cranked before w/o it on.

Couldn't spray starter fluid if cover was still on.

Will it run at all on the starting fluid? Even for a few seconds? If not, it's an ignition problem (no spark). Jim

Yes, for the 10 seconds I mentioned. The few times it did run. I guess you're missing the fact that it just clicks, even after replacing the starter twice. It was cranking but not running until after I replaced throttle body, crank shaft sensor, cam shaft sensor, and MAP sensor. I didn't touch any wires accept the connectors going to each of those items, and the battery ground of course. Nothing else. All are plugged back in properly. I'm stumped. I need a wiring schematic to see voltages. I did a voltage drop test on starter and I'm getting proper voltage. I'm getting proper fuel pressure. It just clicks. I even cleaned cables on top end. Haven't looked at block ground, but I haven't even messed with that.