328 rev problems; not maintaining power

My 1987 328 was running fine when I parked it two weeks ago. Today, it started right up but there is a rattle when I rev it, it backfires, and I cannot get any power to move it. It does not stall and I can rev the engine but it seems rough, sporadic, and does not maintain sufficient RPMs (engine stays running but does not maintain RPMs when revving) to move it out of my parking space; also seems to be a much stronger gas smell than usual. Does anyone have any advice?

 

I think that is correct. Thank you very much for the guidance. I am new to Ferrari ownership and the forum so very happy to have this group as a resource.