My car runs rough. I have a P0301(Cylinder 1 misfire) error code. I have changed the sparkplugs, switched the coil, and have used about a half a tank of gas that has Lucas fuel injector cleaner in it and still have a P0301 error. Fuel injector?

PO301 (Cylinder 1 misfire) can be caused by many different causes many of which requires testing to get to the root causes. Replacing the spark plugs is alway a good idea from a maintenance viewpoint and if simple a easy test to see if one of the plugs may be the problem. After that I would recommend to have your vehicle tested and not to spend additional time and expense for parts that may not fix the problem.