Slant won't drive over 25mph without cutting out

I’ve seen brand new plugs, wires “bleed” electricity.

How’s the fuel filter and fuel pump?

I'm getting a full shot when I pull on the linkage but there's no harm in changing out the filter just in case.

Would either of these issues rear its ugly head only in gear vs. at idle? Because I can rev it up to whatever I want in neutral without a hiccup. It's only in gear when the problem arises.