I have issues! I have a 1984 GMC Suburban. The 350 engine/Carter AFB Carb are newer, however, there are issues with sputtering when pulling a grade. When the engine is at idle, it seems fine and is quite responsive. It's when I am driving, most noticeable when pulling a grade, not smooth at all. I did a fuel pressure test and it is sitting at about 6 lbs but decreases substantially when I hit the throttle. More juice, much less pressure. Is this the problem? Any suggestions? Need HELP!!!!!