I have a 99 Si, when i start it up, it takes 2 times turning it over to start, it didnt do that 2 weeks ago. and when it starts, its fine at first, but as soon as i rev it or the rpms go up, the lights and guages start to pulse. i have a volt meter and it reads 12 before the rpms go up, and once they do it goes to 13.5 and 12.5, and fluxuates between them somewhat fast. its a new alternator. if i let it sit there and run for a min, it chokes itself out. i dont know what it is, any ideas?

 

it sounds like a bad voltage regulator in the alternator. is the belt tight and all the conections good?

 

I had the same problem afew days ago and it turned out to be the alternator, wouldn't hurt to double check.