My DD is a 84 f250, 460, and a 4 speed. The engine is getting a little tired.... when im just cruising down the road in 4th at about 2500-3000 rpm, and let off the gas. It sounds like the engine is loading up then letting loose and i see 12 inch flames come out the Exhaust pipes, what the hell is wrong with this POS i need to get it fixed as i dont want to Chew my swawpers up going to work and back. Any help would be greatly appreciated. if you need more info just ask.