3rd try charm... Mitsubishi 300gt electrical/power problems!?

Question

Car is '99 3000 with 76k mi.... I've been having a problem with the power in my 3000gt it was stalling out becuase it seemed as tho the power was being drained. the bettery gauge would drop to 12volts or under and the car would stall so I had the alternator replaced and I also put in new battery and terminals. then it would be ok when the car first started but after driving for a minute the power battery guage would drop back to 12.5-12 volts when I slowed to a stop and the car was idling(it read 13-13.5 while cruising) it ran without stall 4 2 months and then started stalling again, so i took it to a mitsu dealership, they said the spark plugs had never been replaced and 2 of the o2 sensors were bad. they replace s plugs, sensors, had timing belt service done. now I first start the car the guage reads 14 volts but still after driving when I bring it to idle it still hits 12.5-12 has not stalled ye. (if i put the car in park now the guage slowly rises to 13.5 does anyone know? wtf!

Answer 1

The voltage gauge in the dash is only somewhat accurate. The voltage reading at idle is usually 12.5. If the battery is at a low charge you will see the voltage reading at 14 volts at higher rpms. When a battery is at a fully charged state it will not make the alternator work as hard as if it were discharged so the gauge will read lower. If idle is low enough to make the car stall at idle make sure the throttle body has been cleaned and that the idle circuit is working properly. Many times the throttle cable is too tight keeping the throttle from closing and activating the idle circuit. The two 10 mm bolts(wrench size) on the cable bracket which is on the air intake allows you to slide the bracket and give the cable a little play so the throttle flap closes all the way.