ave gotten in over my head and I’m not too sure what else to suspect for my issue. A few weeks ago, my 1985 cutlass started to backfire under the carb, and had weak acceleration. I replaced all of the spark plugs, and then it was running perfectly. About a week after that, It reverted back to the same state randomly. I had someone tell me that it sounded like water in my fuel, so I added some alcohol to the tank. That got rid of the popping backfires, but not the lack of acceleration and rough idle. I then changed out my fuel filter, and fuel pump. That didn’t fix the issue, but did help. I’d say it was working at about 70%. After 3 days of it being consistent, I went to start it yesterday. It was extremely hard to start, and when it did, it started making the same popping backfire sounds. I am at a loss as to where to look next.