i just put underdrive pullies on my car and now i got a really bad idle and it even died once at a stop sign could this be caused by the underdrive on the alternator and would a better battery and 140 amp alternator fix this?

 

yes,
and no

 

so what can i do to fix it then

 

What kind of underdrive pullies do you have?

I know some people use march performance pullies ect. From what i hear, most had problems with the battery/alt thing and it's exactly what you are expeirencing. The belts are turning too slow to keep the accessories powered up and your running from your battery. 2 things to do possibly, 1) my buddy just put the stock battery pully back on and had no problems. or 2) March has out a line of performance pully system that works to keep the accessories going at the right speed. Call them or check out the website.

 

install the smallest alt pulley you can find.

 

thanks for the info