Sorry, newbie here...

2013 Civic EX-L with 79,000 miles. Living in Phoenix so cold weather isn't the issue!

Over the past week or so my car struggles to start or at a minimum is sluggish.
Turns over great, but once the ignition begins it is starts struggling.
Advanced Auto parts "testing" showed the alternator failed the minimum voltage.
Battery after sitting overnight is holding 12.6V.
Bought a new alternator to put on, but when we got to my friend's house, alternator and battery were showing 14.6V across the system while running.
We just cleaned some corrosion off the terminals and planned to return the alternator.
It's still struggling in the mornings. Yesterday, it was the worst yet and after a quick drive, battery and alternator were only showing 12.6-13.0V while running.
The morning, same thing, but after my 45 minute drive to work, both tested within a normal range of 14.6+/-.

Every other start except the first one of the day starts right up no problem.... Thoughts?

 

Bad battery, starter or battery cables.

The battery should be load and capacitance tested.

The starter amp draw should be measured.

The battery cables should be ohmed out,then voltage drop tested.

Your charging system voltage normal operating range is 12.6v to 15v. As long as it is anywhere in that range ,there are no problems.




I may not be fully understanding what you mean by "struggling" but the above tests are as good a place as any to start.

 

Thanks for the reply!

Starter pulled 123 amps on start.
Battery checked out as well.
Replaced the alternator.
First day did fine.

This morning, it struggled to start. What I mean by that is once the cylinders start to fire, it doesn't immediately start firing to idle rpms. Almost wants to die. Once it starts, it's fine. Again, this is only happening on the first start of the day. I drove 45 minutes to work this morning, stopped for gas and it started again up perfectly. When I leave work after 9+ hours, it'll start up fine as well. Perhaps I should possibly state, this happens when the car sits for 12-15 hours or more...

Now, one other item I just started to notice, but not sure if it has anything to do with the current situation, is after accelerating for a few seconds and I have to let off the gas to coast, the RPMs will drop normally, but "bounce" back up 500-1000 RPM before settling back down. There is no acceleration or jerking of any kind associated with this.