Was the Buddha a vegetarian? Was Sakyamuni Buddha a vegetarian? I've heard that he ate some pork and got poisoned by it when he died? Yet the precepts say that he was vegetarian.

Which one is correct?
The Buddha was not a vegetarian.

The precepts call for no killing, but it does not say that meat cannot be eaten.

A clarification on this can be found in MN55:


  Thus have I heard: At one time the Lord was staying at Rājagaha in
  Jīvaka Komārabhacca's Mango Grove. Then Jīvaka Komārabhacca approached
  the Lord; having approached, having greeted the Lord, he sat down at a
  respectful distance. As he was sitting down at a respectful distance,
  Jīvaka Komārabhacca spoke thus to the Lord:
  
  “This is what I have heard, revered sir: that they kill living
  creatures on purpose for the recluse Gotama, and that the recluse
  Gotama knowingly makes use of meat killed on purpose and specially
  provided for him. Those who speak thus, revered sir: ‘They kill living
  creatures on purpose for the recluse Gotama, and the recluse Gotama
  knowingly makes use of meat killed on purpose and specially provided
  for him’, now, are these quoting the Lord's own words, revered sir,
  not misrepresenting the Lord with what is not fact, are they
  explaining in conformity with Dhamma, and does no reasoned thesis give
  occasion for contempt?”
  
  “Jīvaka, those who speak thus: ‘They kill living creatures on purpose
  for the recluse Gotama, and the recluse Gotama knowingly makes use of
  meat killed on purpose and specially provided for him’, these are not
  quoting my own words, but are misrepresenting me with what is not
  true, with what is not fact. I, Jīvaka, say that in three cases meat
  may not be used: if it is seen, heard, suspected (to have been killed
  on purpose for a monk). In these three cases I, Jīvaka, say that meat
  may not be used. But I, Jīvaka, say that in three cases meat may be
  used: if it is not seen, heard, suspected (to have been killed on
  purpose for a monk). In these three cases I, Jīvaka, say that meat may
  be used.


Regarding the Buddha being poisoned by pork, please see this answer.