General Maintenance & Repairs - Eratic idle and possibe charge problem

When I start my car every now and then it starts with a eratic idle usally searching from 1200rpm down to 500rpm. I on occation it wont start at all and will have no power at all. It has a new battery in it. I have cleaned the TB and MAF. I have also tested the alt. I have 14.6 volts to the alt with no load and 14.8 with load. So I have good power to it but the test still came up with a charging problem. So before I go and pull the alt and get a new one or rebuild it, does anyone else have any other ideas on what it could be. The car is a 01 t/a

Crankshaft Position Sensor....causes all kinds of wierd shit. Will not show a code (at least mine did not) but it will show on an OBDII scanner.

Stop by a dealer and check.

Throwing any codes? SES light on?

I havent had a chance to go see what codes it is throwing but the light dose come on, on the odd occation. It has since I bought the car a year ago. I think it was for emissions so I didnt look into it any.

Would a faulty alt. cause an eratic idle?