What you can do is make one and see if this fixes the issue. Find a good spot in the engine bay, say where there is a random bolt on the frame but nothing really going to it. Optimally, you'll want to test that spot with a multimeter to make sure it's a good grounding spot. If it is, you simply run some wire with crimped ends to it and somewhere stationary on the engine itself. Typical spots to ground on the engine is on the valve cover, intake manifold, thermostat housing, transmission housing, etc.. Spots that don't seem to like additional grounds are the alternator, a/c, and power steering. It really won't hurt to have a few extra grounds, so if you want to run a few you'd be fine.


Below is a pic from a civic I built a couple of years ago. Look at the front of the valve cover on the driver's side. You'll notice a copper(ish) wire running from it to the frame. This is what I'm referring to.