Problems with my 1994 Acura Legend L

I have a 1994 Acura Legend that I just bought a few months ago. Recently found out it was in a little accident from the previous owner and there is some front end damage. Anyways, just recently my car has been running cold. Going down hill my temp gauge will go down to the blue line or below it but while I am driving on a flat road or up hill it will stay a few notches below where it should be. Also I am not getting any pressure inside my coolant tank. Any ideas of what could be wrong??

ive never heard of running cold before but maybe you have a kinked line or hole somewhere.

do you have pressure in the radiator?
if not then theres a line leak or radiator leak

hope it helps