Heres whats going on. For some time now I have been wanting to get a new carb (Holley Street Avenger). I'm pretty sure the carb I have now is the original carb, everything else about my engine has been redone. I hope by getting one, I will have a smoother start up and idle. Now, sometimes I will be sitting at a light, and the car will start to go from 1000rpm down to 800rpm and back up and down repeatedly. And it seems like it might cut off, the idle just slows down. Is this being caused by my modified engine and a stock carb, like maybe the engine demanding more than the carb I have? The holley Im looking at has a electric choke and everything, so would the Holley eliminate the problem?

 

It sounds like it would solve your problem. I have yet to start my car up since i got my carb. i got a holley 4160

 

i think i new carb would help, maybe new manifold? first just try some good old carbuerator/fuel system cleaner from Pepboys.