The engine sputters when floored?

This might be two separate problems, but if the head gasket is blown it can fool the oxygen sensors, a weak MAF sensor or fuel pump can cause this problem. First let's unplug the MAF sensor to see if there are any changes, here is the location. Check out the images (below). Please let us know what happens.

It was worse when I unplugged it.

Okay, let's check for the blown head gasket next, if coolant is being burnt it can fool the oxygen sensors and cause problems.

This guide can help:

https://www.2carpros.com/articles/head-gasket-blown-test

This guide can help as well:

https://www.2carpros.com/articles/car-is-leaking-coolant

Please go over this guide and get back to us.

I will be checking that tomorrow but I was out in the garage letting it run and it does leak coolant.

I could have overheated enough to blow the head gasket which is common. You might need to raise the car up so you can see under it to get an idea of where it is leaking from. When the engine is cold it should run normal?

It was the radiator, I replaced it, but it might be leaking from another spot. I also tested it for a blown head gasket, and it said it was fine.

It also started sputtering when I was flushing it I had turned on the heater went inside came back out 20 min later and it was sputtering.

Is the check engine light on? Does it seem like the engine is misfiring? Can you upload a short video of what the engine is doing? Thanks for the images. Lets go over this guide to run the codes to see if any are stored.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please go over this guide and get back to us.

I have checked several times and no error codes are found.

Okay, then these are two different problems, it sounds like the fuel pump is weak and needs replacement but o be sure this guide will show you how to check it.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Fuel pressure

ITEMS .................... STANDARD VALUE

Vacuum hose disconnected .................... 330 - 350 kPa (47 - 50 psi) at curb idle
Vacuum hose connected .................... Approximately 270 kPa (38 psi) at curb idle

You can rent a fuel pressure gauge for cheap at the auto part store. Here is how to change the pump out in case it fails, please start a new thread for the coolant leak issue. Fortunately you have a trap door so the fuel tank does not need to be removed. Check out the images (below). Please let us know what happens.

Also, it's not leaking I'm just an idiot who saw something dripping but it was because some water had spilled when I was putting it in the radiator.

The engine sounds good thanks for the video. Also, I would check the air filter as well, let me know on the fuel pressure test. This guide may help you as well:

https://www.2carpros.com/articles/engine-has-low-power-output

Please go over this guide and get back to us.

I don't have any idea where to test the fuel pressure from.

Sure, here is information on that, I should have included it on the last post, my bad. Check out the images (below). Please let us know what happens.

I got the OEM fuel test kit from AutoZone, but I can't figure out how to get it on the dumb thing.

Yep, that is the kit, did you go over the diagrams above, it shows how to do the job, you must use one of the fuel line adapters which is shown in the diagrams. Let me know.

I found a crack in the fuel. Rail, i'm going to guess that that's what my issue has been.So i'm going to go ahead and fix that, and then I'll let you know if I still have issues.

Do you know the part number for the fuel rail?

Also would a lancer fuel rail work?

So was the fuel rail leaking? The Lancer fuel rail will work if it is the same part. It sounds like the fuel pump, please met me know I am interested.