I posted this elsewhere, but wanted to get as many eyes on it as possible -
I had previously posted these threads -
Weird voltages - alternator problem? - NASIOC
Alternator life expectancy? - NASIOC
regarding an issue I THOUGHT was because of the alternator, due to the weird voltages I was seeing on the gauge. I brought the car in to have the alternator replaced this morning, and after running their tests on it again, were hesitant to replace it as while it was charging a little low (they said some cars would do that) it would not be affecting the car in the way that I was experiencing (described in the first thread above). Ok fine.
They did some research and noticed a TSB bulletin regarding the cleaning of the ISC valve, hoping it might clear up the stumbling idle. They went ahead and did that, and still, no big results.
They got back to me again and noticed that the car had a pending code of P1590 - Neutral Position Switch - Circuit High Input - (whatever that means) and were curious if maybe that was causing the problem. They cleared the code and test drove it again, it did not come back, but wanted me to bring it back in to have them diagnose it a bit more.
So, at this point, what else could it be? I realize now that maybe the weird voltage readings are just due to the fact that the car is, in fact, stumbling a bit, so the output is going to change.
Any insight would be appreciated. For reference, the car is completely stock, as far as I am aware, other than the factory installed OEM Lamco gauges.