Hey guys. I am sure there are millions of things that may contribute to this but I have a 305 4BBl Quadra Junk that seems to miss and not want to idle just right. I have put new plugs, wires cap and rotor on it. Looked for vac leaks and so on. I just cant put my finger on what is causing this. Any known things this engine is prone to that is a comsumer fix. I dont want to take on rebuilding the engine on my own.
Should I just replace the coil for giggles? I dont want to just toss parts at this thing hoping for a solution.

 

The likelihood that it is the "Quadrajet" (the best street/performance carburetor in existence) is somewhere between zero and 10%.

Ignition - Spark plugs, spark plug wires, distributor cap. Those are the things that can affect one cylinder without affecting all. Did anything change when you replaced these?

Compression - A cylinder low on compression will cause an idle miss. Have you done a compression check?

Vacuum leaks - When you disconnect and plug one line at a time, does anything change? These engines have been known to have intake manifold gaskets go bad, which can cause a vacuum leak on one or more cylinders. A leaking EGR valve can also cause idle issues. The thermo-vacuum switches can also be troublesome.

How does the car run off-idle?