1. The new battery is larger or has a higher voltage than the previous one. This can cause the engine to run rich, which can lead to idling.
2. The alternator belt may be loose or slipping. This can cause the battery to not receive enough power, which can also lead to idling.
3. The Idle Air Control (IAC) valve could be faulty. The IAC valve controls the amount of air that flows into the engine at idle. If it is faulty, it may not be able to control the air flow properly, which can lead to idling.
4. Your fuel injector cleaner bottle may be empty or not dispensing properly. If this is the case, it can cause a drop-in fuel pressure.
If you are not comfortable troubleshooting the problem yourself, it is best to take your vehicle to a qualified mechanic for diagnosis and repair.
