I own a '79 Bronco with a 351 Windsor in it. It is recently rebuilt, polished valves and heads. New 4 barrel Holley, all new everything but the block! Anyways, there's a shade less than 10k on the rebuild and I did a tune-up. New spark plugs, new oil/filter, adjusted idle, new cap/rotor. Checked all wiring, rewired the remote cable on the radio, and added a 12v charger socket. My point is, a week goes by and I'm driving down the freeway at 65-70... when she starts misfiring in Drive. I slow, put it in 2nd, and she stops. It seemed to start at around 2000 RPM, in Drive, sounded like only one cylinder. I checked all spark plugs, cap, rotor, wires, etc. I found what I think would be 1 Left cylinder, or front/driver's side spark plug... was loose. I tightened it and everything seemed to work just great. I fired it up this morning, and it just got worse. I had to drive 20 miles in 2nd, at 20mph or less. Please help? I want to do it right. I've never blogged before, will I get a direct reply... experts would be appreciated. Thanks, S