changed gas cap several times. reset engine keeps repetting after several 100 miles.
check gas cap light keeps coming on 300 miles on 2002 Ford Ranger
Could it be another evaporative emission control system problem, masking itself as a gas cap problem? Is the gas cap sealing area on the filler neck un damaged?
Try replacing your gas cap with a new dealer gas cap, not an after market one. It should help this situation.