Sponsored Links (Register now to hide all advertisements)
Sounds like lean running to me. Could be the jets, fuel line blockage, no vent in cap, vacuum leak, clogged sediment bulb screen, etc, etc; all cause a lean condition.
You can test for a vacuum leak while running the engine at idle, spray some carb cleaner around where the manifold mates up to the engine. If the engine idle changes (speeds up) you've found the leak.