If all of the spark plug wires have been replaced, then the coil for the third cylinder should be replaced. My 1993 Pontiac Grand Am with a 2.3 liter Quad 4 engine is running ruff. It is missing and won't idle. The injectors are functioning. The plugs show signs of weak spark the other cylinders are fine.
Compression tests show all cylinders good.
The coils have been checked. The ignition module replaced. Your reported symptoms would point to a breaking down of spark plug wires. Replacing them should fix your problem. Additionally, the car sometimes stutters on acceleration after a stop.