Most times the amperage rating is on the alternator, it will vary based on the engine/trim package, but somewhere around 120-140 amps for your vehicle should be good. Voltage should be about 13-15 volts at idle. Here is a good article on charging systems: http://bit.ly/LEf0
Thanks Bret, It's my sons truck and he's about 350 miles away so I can't get a meter on it myself. Anything other than a malfunctioning tester (autozone) make it test 1.8 to 2.3amps and 14.4 volts ? I did find a service bullitin on this truck for a short in the alternator wiring harness. (rubbing on valve cover?) Oh and autozone sold him a battery and an alternator but it still tested the same.
Good catch on the service bulletin, that is the sort of thing that could cause this problem. The reading you give for the amps doesn't seem right. When checking amperage output from an alternator, it will be much higher than those readings, especially with a voltage of 14 volts. He may consider finding a different place to take it to since this problem is more complicated than a battery/alternator.