Ok , this behavior can be cause by various things...
1. Sparks... Check if all are ok , no deposits , not worn or shortcirquited from overfueling.
2. Spark cables... Also check if they have cracks or if they are tightly plugged .
3. Fuel filter. Check if it is clean or doesn't have any leak.
4. Humidity. Go to a gas station or similar and use air to dry spark plugs and any electrical connection
5. (and more serious) . Check timing as there is a chance one belt to jump one or more tooths. This can cause similar issues , increase in fuel consumption and therefor emissions issues and also lack of power.
6. Get Super Uleaded in the tank and probably use some additive as there is a chance that there is water in the tank or worst , bad fuel......
Sprint 1.7 '85