My Car Shuts Off After Alternator Install

nursechili`

New Member
Oct 4, 2015
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I have an automatic 2006 Mustang GT Premium Convertible, it just hit 80,000 miles this week and it has nothing performance done to it.

I just changed my alternator for the second time in a year. Except now after changing my car is dying on me when I come to a stop or am driving low speeds like 5-7 MPH. If I'm just idling with my foot on the brake the idle is low around 600 rpm. If in neutral or park it'll go back up to the 750 or so it should be at.

Going to work in the morning as I come to a light the rpms will just drop, car shuts off no warning and the battery light and i THINK the check engine light come on. Turn ignition off, turn back on and pretty much no problem unless it happens again.

I thought this was only happening in the mornings when the car was cold but I was just driving around for a half hour and I was driving really slow through a packed parking lot and it happened five times in a row in 2 minutes.

There is no CEL, I had advance auto check my alternator and battery they said both check out no problems.

I don't even know what to check now but my car can't keep dying on me. Did I damage a sensor or something? What can I check, what info do you need to help diagnose it?

Thank you!
 
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nursechili`

New Member
Oct 4, 2015
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I see this is general talk and I dont know if theres a specific section for this. I have no idea the problem so I dont know where to put it, thank you :)
 

nursechili`

New Member
Oct 4, 2015
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I ordered the correct 135 amp alternator but have no real way of knowing it its the correct one...would it cause the problems if it werent the full 135?
 

nursechili`

New Member
Oct 4, 2015
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Oh I forgot the car will sometimes lurch forward quite hard like I gave the throttle a quick stab. This happens as I'm coming to the complete stop.
 

Svtpilot

Founding Member
Jun 16, 2002
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Long Island, NY
Assuming your battery died and/or you disconnected it while replacing the alternator the computer may need to relearn the idle and fuel trim strategy. I'm pretty sure the procedure is in your owners manual.But if i recall after disconnecting and reconnecting the battery:
*Start the car in park and let idle for 1minute
*Turn on the A/C for 1 minute
*Drive the car for 10 miles varying the speed.
Double check you owners manual but I think that's it. Hope it helps.