I have a problem that just started. Below 3000 rpm and at idle the car runs really rough, sputters and hesitates but above 3000 rmp it runs fine. I replaced the cap/rotor/plugs and plug wires and it didn't help. What's happening?
I'd start by looking for a vacuum leak, visually check all vac lines and the rubber connectors. Listening for these leaks sometimes helps.
Lean is a possibility but rich is another possibility. I remember handling a problem like that and found that rodents had a nest inside of the air filter housing and one of their nuts (acorn possibly not the other type you might have been thinking of! lol ) had lodged inbetween the fuel distributor body and its plate keeping it always slightly raised.
Control Pressure Regulator (AKA WarmUp Regulator) might be defective too!
Year of the Rabbit could help out here! It might have an 02 sensor that is defective or short>
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