Apologies in advance for posting this, I know for a fact that this has been covered at least once in the past 2 months, but with the search feature out of commission I'm forced to annoy you gurus. Enjoy.

My car recently developed a habit of idleing low, about 500rpm on the tach, idles very roughly. The idle will increase or decrease depending on the amount of electrical load. For example, when I leave work at night and turn on the car, the idle drops VERY low while opening the windows/sunroof with the stereo and headlights on. If I turn off the headlights, the idle will improve by 100 or so RPMs. During the day with just the stereo on, the idle is closer to 700rpm.

This mainly occurs while the car is cold. Once warmed up, the idle is right at 900rpm where it has been since I bought the car. It may be my imagination, but it seems the idle is worse when I stop the accelerated warmup via putting the car in gear vs. tapping the gas. Not 100% sure on that one but thought I'd throw it out there anyway.

Today, when leaving for work, the idle dropped enough that the car died. This is the first time in over a year of ownership that the car has ever died on me.

I recall reading about the BAC controlling idle, and was wondering if it is failing to compensate for the alternator's load? How would I go about checking the BAC? Again, I can't search or else I most likely wouldn't be making this post right now.

Car is a 1990 GXL.

 

Too late to edit, I also have a minor problem with the car studdering under light load. I'm not sure if this is related or not, but again, I thought I'd throw it out there just incase it was.

 

TPS

And idle should be 650 to 700 on a manual tranny when warm, not 900