Car Forum World

We recently bought a 2007 dodge ram 1500 4.7 liter with flex fuel. It shakes ALOT!! It will shake on start up and when at stop lights. you can feel it through out the whole truck! It began when we changed the plugs, filled the tank and changed the oil to synthetic. The plugs were rechecked and changed. We tried plus gasoline and still no change. Could it be the synthetic oil? Could we use a fuel injector cleaner with a flex fuel engine? If you have any insight on this please let me know it is very annoying I just want it fixed!! Thank You