aftermarket fuel gauge

All rally inst panels have a 3 post fuel gauge. The gauge voltage limiter is inside that gauge. For this thread, since oil and temp gauges do work, we know the IVR is not the problem no matter where it is located. If/when that limiter fails ( and it will eventually), you will have to pull the inst panel and that fuel gauge to fix it, or install 2 more aftermarket gauges for oil and temp.
All 3 OEM gauges and senders operate on the same 80-10 ohms range. Aftermarkets 70-10 gauge is close enough. Good luck