I'm not sure how deep you have gotten into it yet but one often overlooked fuel starvation problem is the gas cap. Our 7s & 8s use a vented gas cap if you use a non vented voila starvation problems. A lot of crappy venders will sell non vented 69 and later as stock for 7&8 and are so poorly made that they fit loosely and you can kind of get by because it can vent through the loose fit. The problem is it can still cause intermittent problems. Also if you have the correct vented cap the valve can get clogged causing the same issue. in extreme cases you will hear whooshing noises when removing the cap for refueling. To test just use your mouth a little gas never killed anyone. Good luck.