Fixing my 2001 2500 magnum: CEL

Just bought a 99% rust free green 2001 2500 with a plow. CEL was on, massive exhaust manifold leak. I took it for a ride around the block and bought it, figured I'd just get the manifold replaced.

So I'm driving it home, and the rpm's are unusually high, and it's not hitting 4th till 55 mph. 10 minutes later I'm struggling uphill and cel starts blinking. 10 minutes later I'm at autozone a stones throw from my house and a decent garage.

Diagnostics as follows (I had like 4 receipts so this is a breakdown):
- Random cylinder misfires, probable causes: "plugs, wires, coil, vacuum leak, injector, high or low fuel pressure."
- Cylinder 5 misfire, probable causes: " "
- Cylinder 7 misfire, probable causes: " "
- EVAP large leak detected, probable causes: Defective loose or missing fuel cap, EVAP canister broke, hose cracked or not connected, purge or vent soleniod defective, vacuum leak at engine.

Based on all that I'm thinking I need plugs and wires cause the ones in there look mad old... And a new exhaust manifold. I remember when I got a mid-pipe leak in my 97' integra it shook the whole car and made it really sluggish. That was 1.8l, this is 5.9l, and the manifold sits right next to the engine under the hood phucking up fuel ratio. I had to keep the windows down all the way home because I thought I was going to pass out.

I'll keep updating but any input would be greatly appreciated. It really is a nice truck but deep down I'm a little worried it could need engine work. I probably only have 1k cash to drop on repairs right now, and I'm not taking a loan for anything unless it's going to make me money. This truck wont make me money till first snowfall

You're on the right track: do the ignition tune up, fix the manifold and see where that gets you. You should probably go ahead and do a compression test on it while you're changing the plugs just to see where you're at. If the cat is clogged or whatever you could have cracked heads as well.

Great advice posted already, the only thing I would change is do the comp test before you spend a penny on parts.