ZDriver.com - 1988 300zx not starting

hello, i own a n/a 1988 nissan 300zx 2+2. one day after driving i turned the car off and then i turned it back on 5 minutes later and the starter wouldnt even turn but the battery worked and was charged fine. i replaced the starter and the new starter slowly turned. the car would only start half of the time so i would have to jump it off. then i went and bought a new battery, i installed the new battery and its still the same problem. i have narrowed it down to a couple possibilities
1.starter is not correctly installed therefore not getting enough current
2.negative cable that is connected to starter could be faulty
3. there is a vacuum line that is cut and i do not know where it goes. it is on the far right next to the MAF sensor. i know that in my 86 there is a pipe to connect it but in the 88 that small pipe is not there and there is no sign of a broken piece there.

if anyone can send me a picture of a 1988 non turbo maf sensor with the solenoids by it then that would be great. the vacuum line is connected to a soleniod but i dont know where that leads to. i would like quicker responses so if you can respond to be by text that would be good. 478-952-0357