I could use some advice. I have a 99 F350 with the six speed. Between 1000 and 1500 rpm's the motor shudders really bad. I'm thinking bad fuel, but other people have told me to have the computer reset. I have changed the filter twice in 1000 miles...the second time I don't think I needed to. I'm at a loss and worried that I'll damage something if I don't do something soon. Clogged injectors, bad fuel, computer, freakin' gremlins, I have no idea! Any and all help is appreciated. Thanks.