86 fc runs when it wants to

[sidewaysFC]

My cousin pulled in to my house a few days ago in his blue 86 na rx7 rell early in the morning and said ''I think I blew a seal''. I could hear it in the back ground running realy shity so we walked over and the moter was shaking like crazy he said he was just driving down the high way and he lost a bunch of power and it started running like crap. then he took it back to his house and as he was leaving it kinda spuderd down the road and was back fireing a lot. then he called me 10 mins later and said it stald when he was pulling in to his drive way and he poped the clutch to start it back up and then it ran fine then I went over after school and he started it up and it ran fine. but now it wount start at all. we checked for spark so far it has spark but this weekend or next weekend were taking the upper intake off and replacing his vac lines and checking every thing out under there.