Rough idle and check engine light

Since this only happens cold, have you checked the engine coolant temp sensor? If it is telling the computer the wrong temperature when cold, it could cause the air fuel mixture to be too lean or rich.

If you have a live data scanner, check it cold and see if the temperature is close to the ambient temp.

Let me know.

Joe

I'm starting to question if it is an issue with the intake runner intake position sensor. Not being there is making these test take long. I'm sorry for that. However, I need you to check the runner position sensor. Here are the directions. The attached pics correlate with the directions.

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Intake Flap Motor/Intake Manifold Runner Position Sensor, Checking
Vehicle Powertrain Management Fuel Delivery and Air Induction Variable Induction System Variable Induction Control Valve Testing and Inspection Component Tests and General Diagnostics Intake Flap Motor/Intake Manifold Runner Position Sensor, Checking
INTAKE FLAP MOTOR/INTAKE MANIFOLD RUNNER POSITION SENSOR, CHECKING
Intake Flap Motor/Intake Manifold Runner Position Sensor, Checking

Use only gold-plated terminals when servicing terminals in the electrical harness connector of the Intake Flap Motor (V157)/Intake Manifold Runner Position Sensor (G336).

Special tools, testers and auxiliary items required

Multimeter.

Wiring diagram.

Test requirements

The Engine Control Module (ECM) ( J623) fuses OK.

Battery voltage at least 12.5 volts.

All electrical consumers such as, lights and rear window defroster, switched off.

Vehicles with automatic transmission, shift selector lever into position " P" or "N".

A/C switched off.

Ground (GND) connections between engine/transmission/chassis OK.

Ignition switched off.

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to => [ General Diagnosis ] See: Computers and Control Systems > Initial Inspection and Diagnostic Overview > General Diagnosis.

Start diagnosis

- Remove engine cover - arrows -.

Pic 1

- Disconnect the Intake Flap Motor (V157)/Intake Manifold Runner Position Sensor (G336) electrical harness connector - arrow -.

Pic 2

- Switch the ignition on.

- Using a multimeter, check the Intake Flap Motor (V157)/Intake Manifold Runner Position Sensor (G336) electrical harness connector terminals 1 to 3 for voltage.

Pic 3

Specified value: about 5 V

- Switch ignition off.

If the specified value was obtained:

- Replace the Intake Flap Motor ( V157)/Intake Manifold Runner Position Sensor ( G336).

If the specified value was not obtained:

Checking wiring

If the manufacturers test box is being used. Perform the following step.

- Install the test box. Refer to Fuel Injection and Ignition Repair Information

If the manufacturers test box is not being used. Perform the following step.

- Remove the Engine Control Module (ECM) (J623). Refer to => [ Engine Control Module, Replacing ] See: Engine Control Module > Removal and Replacement > Engine Control Module, Replacing.

- Using a Multimeter, check the Intake Flap Motor ( V157)/Intake Manifold Runner Position Sensor ( G336) electrical harness connector terminals to the Engine Control Module (ECM) (J623) electrical harness connector T60 terminals for resistance.

Pic 4

Specified value: 1.5 ohms Max.

If the specification was not obtained:

- Check the wiring for an open circuit, a short circuit to each other, Battery (+), and Ground (GND).

- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:

- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] See: Computers and Control Systems > Scan Tool Testing and Procedures > Diagnostic Mode 04 - Erase DTC Memory.

- Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to => [ Readiness Code ] See: Computers and Control Systems > Monitors, Trips, Drive Cycles and Readiness Codes > Readiness Code.

- End diagnosis.

If the DTC does return and no malfunction is detected in the wiring and the voltage supply was not OK:

- Replace the Engine Control Module (ECM) (J623 ). Refer to => [ Engine Control Module, Replacing ] See: Engine Control Module > Removal and Replacement > Engine Control Module, Replacing.

- Assembly is performed in the reverse of the removal.

Final procedures

After repair work, the following work steps must be performed in the mentioned sequence:

1. Check the DTC memory. => [ Diagnostic Mode 03 - Read DTC Memory ] See: Computers and Control Systems > Scan Tool Testing and Procedures > Diagnostic Mode 03 - Read DTC Memory.

2. If necessary, erase the DTC memory. => [ Diagnostic Mode 04 - Erase DTC Memory ] See: Computers and Control Systems > Scan Tool Testing and Procedures > Diagnostic Mode 04 - Erase DTC Memory.

3. If the DTC memory was erased, generate readiness code. => [ Readiness Code ] See: Computers and Control Systems > Monitors, Trips, Drive Cycles and Readiness Codes > Readiness Code.

End of diagnosis

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Let me know.

Joe

Welcome back:

Certain, no. Questioning, yes. The symptoms are common to specific things, but everything is checking good. Also, the voltage is actually good.

I'm starting to run out of thoughts. Have you checked fuel trims when it is first started and you experience the issue?

The broken hose can be your issue. As far as fuel trims, they need to be as close to 0 as possible. If the trim is in the positive range, the fuel mixture is lean and the comp is adding fuel to compensate. If the trims are in the negative range, the mixture is rich and the comp is trying to remove fuel from the engine. As you already know, a lean or rich fuel mixture can be only caused by so many different things. So, based on the readings, those are the things needing checked.

That is just a general idea of how it works. It can become much more involved, but I'm just trying to help you understand. Hope it helps.

Let me know what they are when the problem is happening. It has to be then because the engine is running in a closed loop before it reaches a specific temperature. It may be very helpful.

Take care,
Joe

Welcome back:

The STFT are not present on the scanner. Does it change when it warms up?

Joe

Looking at the codes, there are several things that can be causing the issue. The hard start really leads me to believe there is a fuel pressure issue and one of the codes indicates an issue with the regulator. Additionally, the EVAP code can be causing a rough idle.

At this point, I would pick one thing at a time and focus on it, specifically the fuel pressure concerns.

Let me know if I can help.
Joe

It will matter what is wrong with the turbo. However, I don't see how it can affect the electronics of the items indicated on the scanner. You have low voltage to them. That is usually an issue with a connection.