I have a 1986 Chevy 454 which I just recently changed the plugs and wires on. Now, the engine idles rough. I also have almost no acceleration, especially when going uphill. It also will occasionally backfire when going uphill. After about 45 MPH, it runs perfectly. I have double checked that all the wires are connected in the correct order. I did not change the distributor cap or rotor, although I did remove it and cleaned the contacts. What could be causing these problems? The truck ran fine before. Thanks for any help!