Q: My 1978 dodge 318 idles fine, but sputters and dies in gear.

If the problem started before you adjusted the mixture but adjusting the mixture allowed you to get the vehicle started, the problem is probably fuel related. You can test fuel pump output and pressure to see if those are in an acceptable range. Of course, check for a clogged fuel filter as well. The stalling you are describing probably stems from a fuel and/or ignition system fault (check to see if the timing advances normally) although air induction could be an issue including the possibility of a large vacuum leak from, for example, a leaking brake booster (if equipped) and/ or the PCV system. If you want this stalling diagnosed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an engine stalling diagnostic and the responding certified mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.