Just recently in my '85 Z28 I have been experiencing what seems to be hesitation when I drive. It's fine at idle, but under normal driving conditions it "surges" in what feels like a misfire but it's not. When I get into it it's ok too, less pronounced. My ignition system is all new, plugs, wires, cap and rotor. Is it a vacuum leak?? Please advise because I have run out of ideas.

fyi : it is a carb'd 305

 

i'd check the fuel and air filters and maybe the cat

 

My cat is only two seasons old. It's a catco aftermarket. The air filter is a K&N which is 2 seasons old. On the other hand, do you think maybe there's a fuel delivery problem? The carb was rebuilt 2 seasons ago also. Will a failing fuel pump cause that skipping? please advise, thanks.