Check and clean your ignition points, plug, cap and rotor.
Change your fuel and air filters.
Check your ignition timing.
Nearly all problems attributed to K-jet injection are caused by ignition problems.

In the rare event something actually fails, probably, in order of highest to lowest likelihood, the fuel pump, the aux air regulator, or the fuel pressure regulator, but these last 2 are very unlikely. The relays for the fuel pump and these controls sometimes get iffy, but these are pretty obvious because the fuel pump doesn't run.

The oil switch wire insulation always seems to get burnt to a crisp by the exhaust manifold. It usually still works if connected and not grounding to anything else. Yours must be grounding.