Thanks Steve83, The truck has one of the fuel injectors leaking fuel badly. i could probably replace just the o rings. the truck has had a bad miss to it at idle and at normal driving conditions but as soon as i stand on it the miss disapears compleatly and runs verry strong and smooth. but as soon as i get off the gas and drive at a steady speed it starts to miss badly again it misses so bad at times it is almost bucking. i have had it to several shops including the Ford dealer, $700 later still missing. we have changed plugs,wires,cleaned throttle body,changed fuel filters. i dont think that the fuel pump has been changed. i have tollerated this miss for along time. but it has gotten so bad that it is un drivable. i just had the motor rebuilt at 183,000 miles and it still has miss. i am just a little lost on were to look other than injectors and fuel pump.