Intermittent issues of hard to start, misfiring, stalling and poor gas mileage

Hi Will,

If you force fuel into the tank after the pump automatically stops, it can cause fuel to enter the EVAP canister. However, I don't think that would be the cause of the issues you mentioned. Yes, it can cause issues, but not all the ones you experience.

The idea that it is hard to start, poor fuel mileage, misfires, and stalling leads me to think there is either high fuel pressure due to a faulty pressure regulator or the engine coolant temp sensor is inaccurate.

Here is what I need. First, are there any diagnostic trouble codes present? If there are, let me know what they are.

Next, if you have access to a live data scan tool, I need you to check two things. First, when the engine is cold and before starting it, check the ECT signal. It should be very close to ambient temperature.

Once you start the engine, allow it to warm up and read the short-term fuel trims. Let me know what they are.

If you haven't already, make sure the fuel pump pressure is within the manufacturer's specs. Here is a link showing in general how to test fuel pressure:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

One other thought. I noted that injector 3 was replaced. Is that something that continues, a misfire on that cylinder? Does it also include cylinder 4? This particular year (along with a couple before it) had issues with the cylinder heads cracking between the two cylinders. It's just a thought.

The pics below are the directions specific to your vehicle for testing fuel pressure. They include the specs as well. If you don't own a fuel pressure gauge, most parts stores will lend one to you.

Let me know what you find or if you have other questions.

Take care,

Joe

See pics below.