A colleague of mine had a 1980 Oldsmobile Omega which had that 2.5 I4 engine with the carburetor. He had a similar problem and it was something in the base of the carburetor. One shop he bragged about solved the problem by removing the carburetor and hammering something. Unfortunately, the job only lasted a month and the problem reappeared and the first shop and managed to crack the bottom of the carburetor which opened up and made the problem worse. I recommended a different shop to my colleague and he left the car at that shop. Unfortunately, the shop was located next to a railroad where the cars went under the tracks on the road. The area had a flood and the Oldsmobile Omega was in the flood and the water was up to the roof. Thus. the problem never was fixed.
Another colleague had a 1980 Chevrolet Citation which he purchased new in 1979 when these cars hit the market. This Citation had the 2.5 I4 with a manual transmission and the clutch, transmission, and cv joints were always a problem.
The university where I taught had the Chevrolet Citations and the Chrysler K-cars in its fleet. I taught an off-campus class at a military base about 65 miles from campus. I preferred the Chrysler K-car to the GM X-cars, but I had no choice as to which vehicle I would be assigned. However, none of the vehicles ever let me down.