Two problems related to tank mounting have been reported for the 1997 Ford Ranger. The most recently reported issues are listed below.
Fuel filler hose cracks prematurely at the connection to the top of the fuel tank resulting in significant fuel spillage during refueling as well as probably splashing out during driving. Fuel vapors surely escape all the time as well. Both situations lead to a serious fire hazard. Seems to be a widespread safety issue based on the amount of Ford Rangers with safety complaints listed on this site as well as discussions on various Ford Ranger forums. The oem Ford part lists for ~$400.
Fuel filler hose. The hoses (both inner & outer crack and cause a significant amount of fuel to spill out from the top of the fuel tank if fuel tank is filled. The hose is an expensive part to replace. I was told by the local Ford dealership that this part is one of the most popular parts they sell. " (the part costs between $225. 00 and $500. 00) plus labor.