[OBS454]

If you did not install it then you have no idea what the previous owner did. Check the entire system from point of origin up to the carburetor. Wrong/improper nipple size on tank outlet... the sock/strainer in on the pickup tube could be restricted... a rubber hose somewhere down the line could be cracked (if mechanical pump is in use)... the metal pickup tube inside the tank could be cracked (2010 /cheap-ass Chinese part installed on 84 Z28 I had to remove gas tank twice) ... weak electric in-tank pump will make enough pressure to run at low speeds but not enough to accelerate... filter at carb ... trash in carb bowl... faulty/improperly adjusted pressure regulator ... fuel tank not vented ... vehicle sat up too long and frigging spider crawled into line, died when gas was added and mummified said spider but did not dissolve said spider thereby restricting fuel flow - true story ... quick tip: on carb side either remove rubber line or install rubber line that will allow you to blow lung air into the line and you should hear/feel bubbling in the tank - that should give some idea of any restriction.