Starter turns over slow in the morning — new battery, what else?

Could be the starter, but check these first: 1. **Ground cables** — the battery-to-chassis and engine-to-chassis grounds are just as important as the positive cable. Unbolt them, wire brush the contact surfaces, and re-tighten. Corroded grounds cause more slow-crank issues than bad starters. 2. **Voltage drop test** — with a multimeter, check voltage at the starter while cranking. Should be 10.5V+ at the starter terminal. If it's lower than what's at the battery, you have a cable/connection resistance issue. 3. **Oil viscosity** — if you're running 5W-30 and it's cold outside, the engine is harder to turn over. Make sure you're using the recommended viscosity for your climate. 4. **Starter draw test** — a weak starter will draw excessive amps. Normal is 150-200A for a V8. Over 250A = starter is dragging. The '08 Tundra with the 5.7L is known for starter issues at higher mileage. The starter is under the intake manifold — not a fun job but doable. The [2008 Tundra wiring diagrams](/wiring/2008/Toyota/Tundra) have the complete starting circuit if you want to do voltage drop testing.

Check your ground strap from the engine block to the firewall. On Tundras it goes behind the intake and corrodes. Common issue, $5 fix if you make a new one from battery cable.