Thank you guys for the advice before, it really helped. Unfortunately, I still have a couple problems. I will try to give you the most accurate description I can..
I bought a 2000 Lincoln LS 3.9 V8 from my father-in-law. The car only has 85k miles. They didn't drive it much. I, myself am just a DIYer. I ran the codes on the car, and 12 came up. All 8 cylinders were misfiring. I ordered the parts and replaced the Plugs, Coils, and Valve Cover Gaskets (not to mention the entire driver side window assembly).
Now, only 1 code comes up, and its a combustion lean code on the left bank.
So, the car is now running with GREAT improvement. The problem is, when I go to accelerate up hill, or when getting up to speed on the highway, it shakes for a minute, and the check engine light flashes. If i let off the gas, or the road flattens out, it will stop.
There is also an oil leak I'm guessing because whenever I come to a stop there's smoke coming from under the hood. I believe one of the gaskets I replaced didn't fully seal.
So basically after replacing everything, I'm just wondering if anyone can give me any advice on what to do next.
Thank you so much!