What is causing my engine to turn over slow?

Alternator failing, voltage loss in main power and grounding cables, ECM charging circuit inoperative, bad battery. Just cause something is new doesn’t mean it’s good.

Answer not posting

All electrical connections should be clean and tight , The starter/batt cable should be in good condition but it's probably the crappy starter , Try rock auto/AC Delco or dealership for an OEM part . I don't buy from auto zoo or nipa

On an 07 model you could very well have a dirty or corroded electrical connection creating high resistance in the starting and or charging circuits. Check all your connections, load test the battery, bench test the starter and alternator as well. Remanufactured units are very often defective right out of the box. One last thing, make sure you have the correct battery with the correct cold cranking amps (CCA) for the vehicle. It's also not uncommon to be sold the wrong battery by the 18 year old counter person at your local auto parts store! Hope that helps! Jim

New "REMANUFACTURED" does not mean its good, slow spinning starters is a good indicator that the winding in the motor has a high draw short, the little Chinese guy that built it gets paid for quantity not quality. Start w the basics check conections at both ends at starter and battery and on ground to vehicle and battery. White powdery "dust" on trans connection is very common in salt climates and in states that salt roads corrosion is a BIG problem. If connections are clean and check out. I would look to starter. Stay away from durafail and twat o zone one out of four starters will fail just ouside warranty or w in 6 months. My personal exp as an ASE 30+ years exp.