Engine specs in sig below. Replaced mechanical fuel pump with a new one a few weeks ago (I don't think this is problem). Ever since then engine performance seems to have gone down. I can't really tell at higher rpm but at lower I can. Generally when I'd pull from a stop, without dumping the clutch I could put the pedal to the mat and it would spin. The last couple times I drove it, it wouldn't do this. Otherwise the car seems to run fine. Starts easy, idles, cruises, no misfires or stumbles, just doesn't seem to have that lower rpm "umph". Accelerator pump is working and all plug wires are snug. Any thoughts? I wouldn't think the new fuel pump would have anything to do with it but that's when I noticed this starting. If I had a cylinder not firing for whatever reason, don't you think that would be pretty noticeable? Carb adj? Check wire spark? When I started looking around there was a loose plug wire but when I snugged it up that didn't change anything. Bad plug now?