Hi Scotty I need your advice bad. 

I bought my 2006 Ford expedition four-wheel drive automatic a few months ago. It has 145,000 miles on it. Approximately 1 week after I bought it. It started running rough. I took it to a mechanic The code in the system was p304. Cylinder 4 misfire.

The mechanic told me I needed a new set of spark plugs. I told him to go ahead and do it. Unfortunately he broke two spark plugs off one in each head. Even with attempting to use the extractor tool he was unable to extract the plugs. 

I then took the car to a different mechanic. He was unable to extract the plugs as well but he pulled the motor and installed two used heads from a junkyard. new timing chains. All new coil packs for motorcraft. All new spark plugs. And a fuel injector on cylinder number 4. After getting the car back with the new heads. The cylinder for misfire returned. After watching some of your videos I decided to clean the throttle body. I removed the throttle body and cleaned it thoroughly. When the motor was removed the mechanic told me that the transmission had a cooler line delete kit on it. We did not correct that situation out yet. I'm not for sure if that would have anything to do with my problems or not. I also unplugged the PCM checked the plugs and pins to ensure nothing was broken bent or missing to the best of my ability it looked okay.

The point I'm at now is the car still runs rough. 

The car does not like to go up hills If it does it usually throws the cylinder for misfire code. 

Sometimes it runs okay for a hundred miles or so. After driving it for a little while it stumbles on acceleration and when I give it gas it definitely doesn't like it every time. We drove it on a trip from Cincinnati to Myrtle Beach. It threw a lot of codes during the trip here they are.

P300

P304

P305

P0022 camshaft position timing over retarded bank 2.

P0453

At this point I feel like we have spent a lot of money on this car in mechanics have guessed a problems and nothing is resolved the issue. I sincerely hope you have some advice that could help me out in the situation.

Very appreciative Daniel Raggard