Well I hate to say this but here goes anyway,the fuel pump eccentric sounds like it has came loose,I have seen this happen before on a friends car and he described the same symptoms,I finally talked him into letting me pull the fuel pump and we used a mirror to look in there,it would run sometimes and sometimes not with all the same symptoms you listed.we pulled the timing cover and pulled the bolt the rest of the way,had to replace the woodruff key and put her back together and viola'.end of story.and sounds like timing chain should be changed while your in there,look over harmonic balancer for wear groove and maybe put a seal saver if it needs it too.Good Luck Curtis