Read this sometime in late 1980s / early 1990s. Survivors of a human vs. robots war are trekking across a barren landscape. They stop at an underground cavern, one of a network established by the human resistance. Only to discover that the food stores have been poisoned by the robots.
To be clear, this isn't The Terminator albeit it clearly shares many similarities.
I think this could be Great Sky River by Gregory Benford.
This is the 3rd novel in the authors Galactic Center Saga and was originally published in 1987, which fits nicely into the OP's timeframe in the question.
Great Sky River is set some 30k+ years into a future where humanity has spread towards the Galactic Center, but met a mechanoid civilisation and subsequently lost a lot of technology as the mech's tried to wipe humanity out.
After the events of Across the Sea of Suns, small groups of humans have settled on other star systems. However, there is a constant threat from the Mechs, a civilization of machines left over from other civilizations and evolved to see all biological civilization as unstable and dangerous.
This novel centres on the "Family" bishop on the planet Snowglade, the mechs are slowly transforming the planet to make it more hospitable for them (less water, a drier climate etc), and the Bishop family is constantly on the move trying to be remain hidden from the mechs or at least as un-noticed as possible. Very little human civilisation exists on Snowglade, humans tend to live in the shadows of mech civilisations, so Snowglade appears quite barren. There is on massive human city (iirc called an Arcology), where the Bishops take a rest for a while but are soon forced to move on again.
The Family, during one of their periods of flight come upon various caches (food, tech etc) left by the previous, more advanced human civilisations from before the mechs started . one of these is IIRC poisoned in some way and I think it does lead to the death of a number of family members.
On Snowglade, there is a particular mech named by the Bishops as "Mantis", this mech both hinders and assists the Bishops for it own reasons and ends, sometimes at the expense of the mechs as a whole.
