ok I still can't figure this problem out@!

I've exchanged the battery and the glow plug timer with another 300SD and that one's running fine and this one keeps getting stuck. A new alternator (with voltage reg) did not help either. Seems as though the car just doesn't charge up enough. Jump Starting will ALWAYS work. This car is always around town (i.e. limited highway driving). I did the test-light current leak with a multimeter test too and have only 40-50 mAmps Draw.
Q)
1. Can a bad glow plug cause an excessive draw.
2. In reading about others, it sounds like around town driving can cause this...should I mess with the idle speed and up it a notch? RIght now it idles right at 500-750 in the dash.
3. To wire in an ammeter, you would need to place in series with the hot wire coming from the altenator?

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1) 84 300SD 285K+ Miles (Ver Calif)
2) 84 300SD 175K+ Miles (Ver Federal)