What can cause Toyota Harrier ACU30 model to have a red hot exhaust manifold just after starting?
The cam or ignition timing is way off or the exhaust is blocked. You don’t say which engine or anything else about the car so that’s the best wild guess I’ve got.
An extremely rich fuel mixture.
The few times I’ve seen this kind of symptom the converter was clogged. One of them was so bad that the manifolds cooked the paint on the hood.
Any diagnostic codes indicating a fuel/air mixture problem? Is the cat getting red hot also?
If the vehicle has the four cylinder engine, both the pre-cat and the exhaust manifold will turn red hot from a rich fuel mixture.