Sounds good. Thanks!
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Update:
Replaced the EGR gasket and O-ring and no changes to idle. Tested the EGR vacuum solenoid valve with a multimeter and showed 32.5 ohms. Also, while idling I opened the top cap and closed the hole with my finger and the car was slowly shutting down.
Also, I did notice a slight oil residue by the PCV (attached pictures). Could this be a possibility?
Additionally, I'm leaning towards replacing/cleaning the purge valve canister solenoid and see what happens.
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Replaced the EGR gasket and O-ring and no changes to idle. Tested the EGR vacuum solenoid valve with a multimeter and showed 32.5 ohms. Also, while idling I opened the top cap and closed the hole with my finger and the car was slowly shutting down.
Also, I did notice a slight oil residue by the PCV (attached pictures). Could this be a possibility?
Additionally, I'm leaning towards replacing/cleaning the purge valve canister solenoid and see what happens.
3
Below is what I could find in Chilton as a generic logical process for investigating a high idle:
Prior to starting this symptom test routine, inspect these underhood items:
Test 2 Chart (Continued)
| Test 2 - Rough Idle or Stalls ConditionLow or slow idle speedFast idle speedHunting or rolling idle speedSlow return to idle speedStalls or almost stalls | - Check for engine vacuum leaks- Check the condition of the PCV valve and lines- Check for excessive carbon buildup- Check for a restricted exhaust (in Section 2)- Check base idle speed, check for low fuel pressure- Check the throttle linkage for sticking or binding |
Prior to starting this symptom test routine, inspect these underhood items:
- All related vacuum lines for proper routing and integrity.
- All related electrical connectors and wiring harnesses for faults (Wiggle Test).
- Check the throttle linkage for a sticking or binding condition.
- Air Intake system for restrictions (air inlet tubes, dirty air filter, etc.).
- Search for any technical service bulletins related to this symptom.
- Turn the key to off. Unplug the MAP sensor connection and restart the engine to recheck for the idle concern. If the condition is gone, replace the MAP sensor.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Step Description: Verify the rough idle or stall » Does the engine have a warm engine rough idle, low idle or high idle condition in P or N? | Go to Step 2. | Fault is intermittent. Return to the Symptom List and select another fault. |
| 2 | Step Description: Verify idle speed & timing » Verify the base timing is within specifications » Verify that the base idle speed is set properly » Are the timing and idle speed set properly? | Go to Step 3. | Set the base idle speed and timing to the specifications and then retest for the symptom. |
| 3 | Step Description: Check AIS / IAC Operation » Check the AIS or IAC motor operation » Inspect the AIS/IAC housing in throttle body for restricted passages. Clean as needed. » Set the parking brake, block the drive wheels and turn the A/C off. Install the Scan Tool. » IAC Motor Tester - Turn the key off and then connect the IAC tester to the IAC valve. » Start the engine and use the IAC tester to extend and retract the IAC valve. » ATM Test - Start the engine. Use the tool to change the speed from min-idle to 1500 rpm. » Did the idle speed change as commanded? | Install an Aftermarket Noid light and check the operation of the PCM and AIS or IAC motor circuits.Check the motor for signs of open or shorted circuits.Replace the IAC motor or PCM as needed or make repairs to the IAC motor wiring.If all are okay, go to Step 4. | If the AIS/IAC motor passages are clean and engine speed did not change as described when the AIS/IAC motor was extended and retracted, replace the AIS/IAC motor.Then retest for the condition. |
| 4 | Step Description: Check/compare PID values » Connect Scan Tool & turn off all accessories. » Start the engine and allow it to fully warmup. » Monitor all related PIDs on the Scan Tool. » Verify the P/N switch input in gear and Park. » Check the O2S operation with a Lab Scope. » Are all PIDs within normal range? | Go to Step 5.Note: An IAC motor count of over 80 indicates the pintle is extended and an IAC count of (0) indicates the pintle is retracted. | One or more of the PIDs are out of range when compared to "known good" values. Make repairs to the system that is out of range, then retest for the symptom. |
| 5 | Step Description: Check the Ignition System » Inspect the coils for signs of spark leakage at coil towers or primary connections. » Check the spark output with a spark tester. » Test Ignition system with an engine analyzer. » Were any faults found in the Ignition system? | Make repairs as needed
| Go to Step 6. |
| 6 | Step Description: Check the Fuel System » Inspect the Fuel delivery system for leaks. » Test the fuel pressure, quality and volume. » Test the operation of the pressure regulator. » Were any faults found in the Fuel system? | Make repairs as needed
| Go to Step 7. |
| 7 | Step Description: Check the Exhaust System » Check Exhaust system for leaks or damage. » Check the Exhaust system for a restriction using the Vacuum or Pressure Gauge Test (e.g., exhaust backpressure reading should not exceed 1.5 psi at cruise speeds). » Were any faults found in Exhaust System? | Make repairs to the Exhaust system. Then retest the symptom.
| Go to Step 8. |
| Step | Action | Yes | No |
|---|---|---|---|
| 8 | Step Description: Check the PCV System » Inspect the PCV system components for broken parts or loose connections. » Test the operation of the PCV valve. » Were any faults found in the PCV system? | Make repairs to the PCV system. Refer to the PCV system tests. Then retest for the condition. | Go to Step 9. |
| 9 | Step Description: Check the EVAP System » Inspect for damaged or disconnected EVAP system components or a saturated canister. » Were any faults found in the EVAP system? | Make repairs to EVAP system (use the EVAP tests in this manual). Retest for the condition. | Go to Step 10. |
| 10 | Step Description: Check the Base Engine » Test the engine compression. » Test valve timing and timing chain condition. » Check for a worn camshaft or valve train. » Check for any large intake manifold leaks. » Were any faults found in the Base Engine? | Make repairs as needed to the Base Engine. Refer to the Base Engine tests. Then retest for the condition when repairs are completed. | Go to Step 2 and repeat the tests from the beginning to locate and repair the cause of the "Rough, Low or High Idle Speed" condition. |
I couldn't find the IAC percentage/duty cycle with my scan tool, but noticed the TPS% at 17.2. Also, when applying brakes during cold starts, the RPM drops a little but no issues at operating temperature. Could it be from the vacuum pressure building up at cold start?
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At idle stop, TPS % should repeat. Move throttle and let it settle. Non repeat will cause bad idle. Pic of data from my TPS. I replaced the TPS and made NO difference. Still not repeating. Back probe the signal and it is unstable when idling. Key on but not running solid stable. When idling, the "return" line is unstable. It is GROUND to the PCM ground. Traced issue to PCM ground at firewall. Bad ground caused PCM to get bad ground and sensors bad signal = not body ground.
When you start, the PCM reads your TPS as idle. In the bad case you press the throttle to start, PCM uses last true idle stop start. That ground is basic maintenance. Ford bolts the grounds over paint. OK when new but it goes down hill with age. Fix easy. As you might guess, I was going working to find bad idle.
-chart-
Attachments
Vacuum pressure doesn't build up. When a gas engine is running, it creates vacuum between the pistons (on the intake strokes) and the throttle (the restriction to air flowing in during the intake strokes) inside the intake manifold. Pressing the brake pedal allows air to flow into the REAR of the brake booster, so that should not affect idle. Releasing the pedal closes the back of the booster and allows air from the back to flow into the front & out to the intake manifold (the vacuum source). When the engine is cold, it's running in open loop, which means it responds more slowly to sudden changes - especially those NOT indicated by any sensor (like how far the pedal was pressed or how fast it was released; vs. the throttle position moving which IS sensed). So the cold idle is more sensitive to the brake being released than the warm (closed-loop) idle.
(click this text)
Thanks!Vacuum pressure doesn't build up. When a gas engine is running, it creates vacuum between the pistons (on the intake strokes) and the throttle (the restriction to air flowing in during the intake strokes) inside the intake manifold. Pressing the brake pedal allows air to flow into the REAR of the brake booster, so that should not affect idle. Releasing the pedal closes the back of the booster and allows air from the back to flow into the front & out to the intake manifold (the vacuum source). When the engine is cold, it's running in open loop, which means it responds more slowly to sudden changes - especially those NOT indicated by any sensor (like how far the pedal was pressed or how fast it was released; vs. the throttle position moving which IS sensed). So the cold idle is more sensitive to the brake being released than the warm (closed-loop) idle.
(click this text)
So, I checked the throttle body today and didn't see any issues. It was cleaned in September, when the intake gaskets and other items were replaced.
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