89 BroncoII gauge issues

It's an 89 XL with the 2.9L V6/5 spd 2wd. I think my problem might be a ground issue, but since I haven't been able to fix it, I'm turning to you guys. The fuel gauge always reads "F". Moves down a little when you first start it, but goes right back up to full. The temperature gauge always reads towards the "C" end. I installed a new temp sensor and thermostat and had the coolant system "burped". Just had the A/C charged. It will get hot just idling in 110 degree weather. still only reads about half way up the temp scale. The oil pressure seems to work some times, but other times it goes to the low end of the scale. I've checked the ground points on the core support and inner fenders. Just not sure where else to test and how to proceed.







