help a newbie with 93 cav?

Ok, I'm totally a newbie on these boards and to cars in general. Know a few things, have service manuals, but no genius.

Have a 93 cav 4 door automatic 220k km. lately, been giving me troubles starting especially when it gets really cold or damp outside (i notice, not hard and fast rule, sometimes won't go even when hot and sunny).

I turn the key, it cranks and cranks, but doesn't turn over. to get it to start, i spray some starter fluid (saved me a dozen times and counting) into the intake manifold (gotta unscrew that and spray while someone's starting with the gas floored).

It sputters to life but it's rough for a few minutes after. Idling, it knocks hard, like when a manual shift car's about to stall.

Immediately starting after shutting down works, wait ten minutes, it doesn't.

Thought it was ice in fuel line (problems first started in march/april), so put fuel line antifreeze. then thought it was fuel pump relay, scavenged junkyard for one, replaced. Nothing works so far, trying fuel injector cleaner tomorrow.

Any suggestions? Was hoping someone would know on these forums. Slowly realizing that these forums are great for research/suggestions: nothing beats human input.

Sorry for the long post, and thanks.