Hey there, I have recently upgraded wiring in my 00 Civic EX. I Have a 1998 Integra LS motor and computer. The Alternator was upgraded to 165 amps and a Optima Yellowtop fullsize was added under the hood. A secondary Stiner 1700 Battery is in the trunk. All Wiring under hood going to the Battery and the rear battery is 1/0 Awg. Over the past few days, i noticed sometimes on stopping as the car slows the rpms dipped below 500 the battery lights comes on and the car almost stalls. It recovers after about 30 seconds or so and sits at about 700-900 and the battery light turns off. I have in the past week replaced the Fuel Filter, Spark Plugs and Wires. PCV Valve, and changed the oil. I reset the computer a few days ago when i installed the new filter and plugs. The vehicle charges excellent with or without the rear battery switched on. What my question is there possibly a issue with the fuel filter, or ive seen in here in posts that maybe i have a injector going bad. I am a car audio guy wiring and car audio related stuff is more my thing, im not really engine savvy. I have taken the rear battery out of the charging loop and it will still do this. Do you have any ideas of what else to check. I know that the fuel filter was a bit of a pain to realign the nut on top to get it flowing well. The Car has done this maybe once or twice since i have had it over the past 2 years. but now it has happened at almost every approching stop i make. Any Ideas would be greatly appreciated.