Primera Poor Starting and Fuel Consumption

I had a similar issue with my Primera. High fuel consumption and starting problems definitely sound familiar. Have you checked the throttle position sensor readings? What about cleaning the throttle body and air intake? Could be a buildup of grime affecting the engine idle.

Throttle position readings seem erratic. I haven't cleaned the throttle body yet. How difficult is it to access the engine throttle?

Accessing the engine throttle can be a bit tricky depending on your experience. You'll need to remove the air intake assembly, but be careful with the sensor connectors. Given the erratic readings, I'd recommend taking it to a workshop. A defective accelerator pedal module would cost you around 205€ to replace including the labor. It's better to have it diagnosed professionally before throwing parts at it.

Thanks for the advice. Took it to the shop, and you were right. Defective accelerator pedal module. Replaced it, and everything's back to normal.