Firebird Help

I have a 1987 pontiac firebird. I have been putting alot of work into the car, but I do have one problem I am unable to figure out. When I slow down, my oil gauge drops, my battery meter drops, and the car always idles low. Most of the time it will stall when stopping. Can someone please help me?

how old is the fuel filter? lots of work into the engine? Have the fuel pressure checked. Tune`r up and clean your carb,maybe tweak the idle if need be. The dropping gauges Could be just from lack of idle speed. Check the battery cables at both ends for corrosion and tightness.

Check for a vacuum leak.

With the above recomendations I add to check the itgntion timing.