1994 Nissan Altima stalls when I give it gas

I have a 1994 Nissan altima that showed no signs of issues and suddenly stalled while I was at a traffic light the other day and wouldnt start again. Got it towed home and began checking things.
Replaced fuel filter, checked fuel pressure, fuel pressure was good, checked for vacuum leaks and cannot find any, we think we may be hearing on on the intake manifold near the firewall but cannot be certain, so we sprayed carb cleaner all over that area and no change in idle speed. No check engine light, we unhooked the MAF to see if that was the problem, nothing changed in idle speed. It is hard to start and once we do get it started it is a 50/50 shot if it will stay started. If we depress the gas pedal it will almost always die. No oil in the distributor cap, we are getting fuel, air and spark and are now at a complete loss. Any help would be great.