You don't need a check engine light to diagnose. It just makes it easier. Based on your description, it sounds like a weak fuel pump. If you are climbing an extended hill, the engine demands more fuel for an extended time. If the pump is weak, it will slowly run low on fuel.
So, that is where I would start. Here is a link that explains how to test a fuel pump. You will need a fuel pressure gauge, but most parts stores will lend or rent one to you.
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
_______________________________________
In addition, if I had the vehicle, I would check what are called fuel trims. This is done with a live data scanner, It indicates how the car's computer is trying to compensate for the air fuel mixture. If it is trying to add fuel, then it is likely a fuel pressure issue or engine vacuum leak.
Here are the manufacturer's specs for pressure requirements:
2000 Chevrolet Malibu V6-3.1L VIN J
Pressure, Vacuum and Temperature
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Pump Fuel Pressure Specifications Pressure, Vacuum and Temperature
PRESSURE, VACUUM AND TEMPERATURE
Key On Engine Off .................... 358-405 kPa (52-59 psi)
______________________________________
I can help you through the test if you want to try it. I have to be honest. Based on your description, there are a few different things that could be checked. I wish I could help you, but the best I could do is help you from here.
Let me know.
Joe
SPONSORED LINKS
Wednesday, April 22nd, 2020 AT 8:15 PM