starting issues

[Boosted_240sx]

So iv got a 89 hatch sr20det, So about an hour ago i went to go buy some chew and when i went to go start my car it didnt wanna start. so i jumped it and it started up and i went inside to let it warm up and after about a minute i could hear the rpm's keep raising and dropping from 1000rpm to 2000rpm. so i decided to drive it anyway down the road to the store and everytime i let off the gas the rpms kept raising and lowering, once the car got up to tempature i turned on the heat and it was blowing out cold air. right before i got to the store the rpm's were finally normal i left the car running while i went inside and when i got back in the car it was blowing warm air. Then on my way home i was a block away and i was taking a turn and i went to downshift and when i pushed in the clutch the car just died on me so i tried to start it again and nothing. So i had to push it home, so i just left it on the street in front of my house. does anyone have any idea what could be wrong here? sorry for the book i just wrote just trying to be as detailed as possible so you guys could maybe help me pin point the problem
thanks,
Dylan

[Boosted_240sx]

so i solved it (i think). i just went and bought a new battery and it runs perfect now, im just hoping that this one doesnt die cause that would mean that the alternator is draining the battery right?

[Cksvlad]

bro, the alternator charges the battery, It doesn't drain it. but yes if you replaced the battery and it fails to start again you should check the alternator belt and make sure it is making good contact so when your crank is turning the belt it's turning the alternator's pulley, and ensure that there isn't any slip on the pulley when it turns. If this is your problem then you need to add more tension on your belt.(PS do NOT add tension if the belt is stretched or has to much wear & tear, At this point just replace the belt.) After checking all your connections, Belt, and Pulley, and none of those were your problem than check the Alternator, an make sure it is properly sending it's output voltage of approximately 13-15, and make sure it is constant, not fluctuating. Then you will need to change your alternator.

[Boosted_240sx]

i bought 2 new belts the other day and installed them and i bought a new battery as well and when the cars running the battery reads 14 volts so it charging just fine. the car runs great now except for that sometimes when i push in the clutch the rpms will drop pretty low to like 400-500 and come back up, not all the time but sometimes, it will never die just bog down. im thinking a boost leak possibly. its not a huge deal though.
thank you for the reply