I have a 1989 Ford F150, 4.9L, 300, straight 6 cylinder pickup. When I purchased it, the engine was "skipping" a bit. I then drove it 90 miles home in that condition yesterday. Today I began to change the plugs and wires to new ones. I noticed that the plug wires of #6 and #1 were switched. While putting the new wires on, I put them in the firing order of 1, 5, 3, 6, 2, 4. And now it is not firing. I checked the fuel pump and it is working properly and fuel is being passed to the plugs. I replaced the distributor cap and rotary button with new ones and checked the coil to ensure it was getting power. However it is still not firing. Any ideas? HELP?