Inconsistent Idling after Battery Replacement?

This is normal as the computer is relearning the engine idle map. I would just drive it and the problem should go away, here is a guide to help you as well.


https://www.2carpros.com/articles/engine-stalls-idles-too-high-low-after-dead-or-replaced-battery/

Let me know how it goes

Thanks for the response; but now we have another issue.

Even with a brand new battery, my car drive fine this morning then while idling in a parking lot, my warning lights flickered and flashed on again and after turning the car off, my car didn't start again.

Does this point more towards an alternator issue; or what could be causing my battery to completely drain even after a brand new one was put in last night?

It sounds like you have a loose or bad connection at the battery, here is a guide to help you fix it.


https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked/

Let me know how it goes.

Thanks again for the quick response; but I checked my battery terminals as soon as my car died and both were tight as could be.

It drove fine for a few hours this morning before dying down and not starting back up parked in a parking lot.

This is why I'm guessing it might be an alternator issue, as the battery is brand new and still won't start after a few hours of driving.

Any other advice or ideas?

Does the battery cables have a after market end on them? These fail due to corrosion all the time FYI. Once the car is running lets check the alternator. This guide will show you how.

https://www.2carpros.com/articles/how-to-check-a-car-alternator/

Please go over this guide and get back to me.

I did have to change out my positive terminal due to a crack a year ago; but there was no corrosion or anything on it.

We jumped the car and got it running; battery tested around 12.2v before cranking and after the jump start and keeping RPMs around 1500 in park, only slowly climbed to around 13v.

Turned on lights and air conditioning for a load test and my dashboard warning lights started to come on again; so I'm definitely feeling at this point it's the alternator between the voltage only reading 13 after a jump start and revving the engine, and the warning lights coming on as soon as I click on the radio, air, and lights.

Yep, that can be the alternator is weak but I would remove the battery terminal end, and get a new one, when the end goes bad it will cause this issue. There will be corrosion under the cable end clamp that you cant see.