I have a Ford Econoline E150 with the 302 engine. I have replaced just about everything I can with the exception of the distributor, but the van still has a skip and shake. I don't know what is causing it. Before it would have issues with wanting to start, but I found it was the fuel pump relay, once I replaced that it starts up every time with no issues. I've changed plugs and wires numerous times, I have changed the ignition coil, and after doing that, the shake seemed worse. Any ideas?