Your voltage regulator should compensate for it by changing the frequency to the field coil of the generator and producing more power. The voltage regulator should compensate for it by increasing the frequency to the field coil of the generator, thus producing more power.
I am having the same problem sounds like the knock sensor OBDII code P0328 or P0327 Try looking up CMU codes using OBD It also could be a clogged Cat being cat has little effect until after exhaust has warmed to a certain point.
You can go to your local auto shop or most hardware stores and look for a brass extension. most American oil pressure sending units usually have 1/8 npt or 1/4 npt threads.
This can be many things. Due to the vehicles age, I would first look for a vacuum leak. Replace all vacuum lines one at a time to avoid getting confused. Very cheap fix. Your Check Engine light should be on. If it is, a scan of the computer can also provide a clue. Of course if the plugs and plug wires have not been replaced or have over 75,000 miles on them, then they need replacing.
Corrupt or missing driver or failing hardware.