Only just saw this again, but there are a few ground points inside your engine bay.
One noticeably is on the left hand side of the engine (if you are facing the car), on the chassis rail? right of your battery.
Forgot where the other ones are, I can check tonight for you guys if you still haven't solved your problems.
And no, the car doesn't need to be on a hoist to access them lol.
Might be worth adding an extra ground or two around the engine bay, or buy a ground kit.