I have a 1990 f250 5.8 4X4 that I am getting close to being a daily driver, thanks to the help and advice from this forum. The truck runs very well but after being warmed up and driven a few miles it cranks over hard, almost like a near dead battery. (Battery is brand new.) My search on this forum suggests that my ignition timing might be too far advanced. My Chilton manual seems to indicate that I have the TFI-IV ignition, since it doesn't have a vacuum line to the distributor, and Chilton states that "no ignition timing adjustment is possible and none should be attempted". Do I really have a timing issue and if so, how do I fix it? Thank you in advance for any help!!