Okay, I attached the PCV location for you.
I would replace the IAC valve. It cannot be cleaned as the part that sticks is not available to clean.
The TPS has no effect on the high RPM. Make sure the voltage is set at.5 to.75 volts at closed throttle.
Roy
NOTE: The curb and fast idle speeds are controlled by the Power-train Control Module (PCM) and Idle Air Control (IAC) valve assembly. The IAC valve is not adjustable. A large increase or decrease in closed plate airflow from the calibrated level will not allow effective idle speed control.
The throttle body incorporates an orifice in the throttle plate controlling idle airflow as part of the sludge tolerant design.
Throttle Body Assembly Decal Location
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Throttle bodies with sludge tolerant design are identified with a yellow/black decal. This decal warns that the throttle plate stop screw must not be adjusted counterclockwise (backed off), as this will not reduce the engine speed but may cause the throttle plate to stick in the bore. Backing out the screw may be required if the throttle body has been previously serviced (a plug in the throttle plate orifice may be present), or the plate stop screw tampered with (TP Self-Test output out of range). The decal also warns that the throttle body must NOT be cleaned inside the bore, as this cleaning will impair the sensitive coating. The sludge accumulation will not affect the idle air flow. The cleaning procedure for the IAC valve still applies.
REMEMBER
A change in idle airflow can occur not only at the throttle body but other areas as well. You should enter the idle speed procedure only after other possible causes in the following areas are eliminated.
Contamination within the idle speed control device
Lack of fuel system control (excessively rich or lean)
Throttle sticking or binding
Engine not reaching operating temperature
Incorrect ignition timing
Incorrect or clogged PCV system
Vacuum leaks (intake manifold, vacuum hoses, vacuum reservoirs, power brake booster etc.
VERIFY
Transmission is in Park (A/T), or Neutral (M/T)
Parking brake is applied (automatic brake release disconnected where applicable)
Wheels blocked
Engine at operating temperature
Proper fuel pressure and no exhaust smoke
Correct and clean PCV system
Heater, A/C, and other accessories Off
Ignition timing is set to specification
EEC-IV diagnostics have been performed and vehicle malfunction indicated diagnostic trouble codes have been resolved.
PROCEDURE
STEP 1
With the engine Off, connect a tachometer according to manufacturers instructions. Disconnect the negative (-) terminal of the battery for 5 minutes, then reconnect it.
STEP 2
Start the engine and allow the idle to stabilize for two minutes. Goose the accelerator, and let the engine return to idle. Lightly depress and release the accelerator, then let the engine idle.
STEP 3
If the engine does not idle properly, proceed with this procedure.
NOTE: In some cases, even if the idle speed is OK, proceed with this procedure if the customer's complaint persists (idle air control duty cycle may be out of range).
STEP 4
Turn the engine Off, and install a 0.025 in feeler gauge between plate stop screw and the throttle lever.
STEP 5
Start engine and run at 2500 rpm for 30 seconds, then return to idle.
STEP 6
Place the transmission in Park (A/T), or Neutral (M/T).
Typical Throttle Return Screw Location
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STEP 7
Using a tachometer, verify idle speed is 704 +/-10 (A/T), or 640 +/-10 (M/T) rpm.
NOTE: Before proceding with this procedure, shut the engine Off, wait ten seconds. Re-start engine and recheck idle for two minutes. This eliminates the possibility of entering part throttle mode.
Throttle Plate Orifice Plug
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RPM TOO LOW
a. DO NOT clean the throttle body, check for the plate orifice plug.
IF NO PLUG, turn the screw clockwise to the desired rpm.
IF PLUG from previous service, remove and adjust the screw in either direction as required. Screw must be in contact with the lever pad after adjustment.
RPM TOO HIGH
a. Turn Off the engine.
B. Disconnect air cleaner hose.
C. Temporarily block the throttle plate orifice with tape. If the orifice already has a plug from previous service, proceed to Step (e).
D. Restart the engine, and check idle speed, using a tachometer.
NOTE: Vehicles with Mass Air Flow Sensors, reconnect the air intake duct hose before checking idle rpm. If the engine stalls, crack open the plate stop screw, DO NOT over adjust.
E. If rpm continues to be fast, Run Key On Engine Off (KOEO) Self-Test.
F. If rpm drops to the the value in Step 7 or lower, or the engine stalls, turn the engine Off, disconnect the air cleaner hose, and remove tape from throttle plate.
G. Install the proper color coded orifice plug, according to the throttle plate orifice size.
H. Reconnect the air cleaner hose, and Start the engine. Check the idle rpm using a tachometer. Turn the plate stop screw clockwise to the nominal rpm +/- 25 rpm shown in Step 7.
STEP 8
Shut the engine Off. Remove the feeler gauge between between the plate stop screw and throttle lever.
STEP 9
Start the engine, and allow the idle to stabilize for two minutes. Goose the accelerator, and let the engine return to idle. Lightly depress and release the accelerator, then let engine idle. If idle problem still exists, check for other possible causes.
STEP 10
Run the Key On Engine Off (KOEO) Self-Test for proper TP code output.
STEP 11
For Automatic Overdrive (AOD) transmission equipped vehicle, check and adjust (if necessary) the throttle valve pressure.
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Sunday, January 12th, 2020 AT 10:30 AM
