New Owner, 2000 Mustang GT Dead Battery Misfire?


New Member
May 12, 2019
Greetings all,
New owner here, just purchased a 2000 Mustang GT one-owner with 43,000 miles (all stock). The car drove great the day I purchased it, but today I went to pick it up from the dealer and things started off poorly with a dead battery requiring the dealer to jump the car. The car had been detailed the day prior to me picking it up, so it's possible an interior light or something left on was the culprit. I decided to continue my 2 hour drive home, hoping the drive would be enough to charge the battery. Around 10 miles into the trip I notice a lack of power when accelerating in 5th gear coupled with a bit of a miss/hesitation in 5th when driving up hills (this is in the Shenandoah nat'l park area).
I decide to return to the dealership and leave the car with them for diagnosis or replacement of the battery and once at the dealership I turn off and attempt to re-start the vehicle with no luck, so the battery is certainly dead. All of the gauges were within their normal operating ranges, and no CEL or BATT light turned on at any point during the trip. Would a completely dead battery cause the lack of power/hesitation or misfire I experienced? I'm excited to have a bone-stock New Edge mustang GT, but today's experience was very disheartening. I'm a Datsun mechanic and enthusiast so I'm not unfamiliar with mechanical troubleshooting, I'm just hoping for expert advice from you mustang enthusiasts. Some of the things I noted while driving are:
1. Good power in lower gears when accelerating from a stop, no idling issues or misfire at idle. No CEL or other warning lights came on at any point.
2. The hesitation/stumble only appears when going up a steep grade in 5th or 4th and when going WOT in 5th on a flat surface.
3. No vacuum lines seem to be disconnected or broken, and I didn't notice any coolant from a cracked intake crossover like some owners note on the 99-01 mustangs
Thanks in advance for any help you all could provide!
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SN Certified Technician
Aug 14, 2009
Houston Texas
Today's cars simply will not run right without a STRONG battery and charging system. IMO every trouble shooting session should begin with a review of the car's charging system as this is the cornerstone of all of the other electrical systems in the car.

Howto perform charging system voltage drop test