Severe Miss When Cold

Q: Severe Miss When Cold

I’m trying to track down a miss during warm up on my bird. In the past, I could start the car when cold and drive away, it would run fine. I’ve noticed a miss that has progressively gotten worse after each day, spanning over the past months. I’ve replaced the distributor cap, rotor, plugs and points but no change. The car starts fine, but it randomly misses, getting better when it warms up. Once at operating temp, it seems to run fine but you can hear it miss a little randomly. Under heavy acceleration there is no stalling of performance, hot or cold. I doubt it’s the carburetor (Edlebrock 650) because the car seems to run fine after warm-up, just a random miss.

One thing. The timing is set really advanced, about 14 degrees BTC. I’ve been running it that way for a number of years. If I set it to 9 degrees there is no power. Also, the manifold vacuum is 18 and steady when hot.

Any tips on what to look for would be helpful.

A: check for vacuum leaks check or replace plug wires replace fuel filter

A: I suspect you don’t have enough choke action. Either insufficient spring tension, sticky linkage, or too much choke pull-off. Generally lean when cold. If you set the timing back it would probably pop back through the carb with all else the same indicating it’s lean.

A: Change the plug wires. The wires are more than likey breaking down when cold since more current is needed then. A good set of Delco wires should do the trick.

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