this probably started on Monday of this week and my battery light came on and i know i had a old battery. Everytime i would be idling my car would start to drop RPMs and even at times it would shut off. So i bought a battery (Optima Red Top). And even yet my battery light still turns on and off..the car never stalled out when i am driving or dropped RPMs just when i am idling at a red light. I brought it to Ford and they said the alternator is running fine and the only problem they saw was the MAF sensor and i had a coolant leak...they said that should fix the battery light problem because the MAF was sending signals to the computer saying i was 3,000ft above sea level and i live in FL. I got the car back today and it did it again the battery light came on and the car just shut off...so what is the problem?