XE. Could a clogged throttle body cause the RPM to increase after stopping?

Could be bad TPS sensor (RPM)

What Colorado do you have ? 2 wheel or 4 wheel drive ? Sport ,sport LS 3.5L , Z71, Z71 LS. etc. what size engine ? an does it have electronic throttle control ? I have factory service info an it is not showing that code .
DTC P0506

Circuit Description

The throttle actuator control (TAC) motor is controlled by the powertrain control module (PCM). The DC motor located in the throttle body drives the throttle plate. In order to decrease idle speed, the PCM commands the throttle closed reducing air flow into the engine and the idle speed decreases. In order to increase idle speed, the PCM commands the throttle plate open allowing more air to pass the throttle plate. If the actual idle RPM does not match the desired idle RPM within a calibrated time, this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:
DTC P0506 Idle Speed Low
DTC P0507

Circuit Description

The throttle actuator control (TAC) motor is controlled by the powertrain control module (PCM). The DC motor located in the throttle body drives the throttle plate. In order to decrease idle speed, the PCM commands the throttle closed reducing air flow into the engine and the idle speed decreases. In order to increase idle speed, the PCM commands the throttle plate open allowing more air to pass the throttle plate. If the actual idle RPM does not match the desired idle RPM within a calibrated time, this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:
DTC P0507 Idle Speed High
Cleaning the throttle body mite take care of it !
Cleaning Cleaning An Electronic Throttle Body Safely

500 RPM or 5000? Reason I ask is the rev limiter shouldn't let it rev over 3500 in park or neutral? If idling at 500 then get an external tachometer and connect it to determine that your gauge isn't faulty! if at 5000 RPM it could be a stuck tps or possibly debris in the throttle body or a vacuum leak causing the idle to increase? Is it idling high or low compared to before it became faulty?

If you need further help, reach me via phone at https://www.6ya.com/expert/james_8f14c50d9c6cdea8

The most common cause of high idle is an intake air leak. It will cause a lean condition to the O2 sensors and the PCM's solution is to increase the fuel mix resulting in faster idle. It can also cause a Check Engine Light if the idle remains too high for too long. Do a smoke test or soapy water test around the intake manifold and throttle body. If you detect any leaks, seal them and try again.

Could be one or both of two things.

1. The accelerator pump in the carb is clogged, the linkage is unhooked, or the diaphram in the pump is bad. It's cheap to replace and comes in the carb rebuild kit. This usually just causes hesitation when you step on the gas pedal. It doesn't usually cause the engine to stop running.

2. More likely is that the main jet in the carb is clogged. At idle, high vacuum under the closed throttle plate in the carb causes fuel to flow thru the idle jet. As the throttle plate opens (as you step on the pedal), the vacuum under the plate dissipates, stopping the flow of fuel thru the idle jet, and the vacuum ABOVE the throttle plate increases, which is supposed to then draw fuel from the carb bowl thru the main jet in the carb. If the main jet is clogged with dirt, then it can idle just fine and die as soon as you step on the pedal.

The problem is that the engine is not being sped up when the extra load is applied. This is commonly caused by the throttle body needing a good clean.

The IAC motor on the throttle body has internal (an unobtainable) nylon gears that sometimes strip.

Worst case, look on the top of the throttel body. There's a 10mm round black cover with a big phillips screw inside it. This is the idle speed. Undo this about 1/2 turn to increase the idle speed a bit. It should be about 750-850 rpm. Try the AC. Repeat as necessary.

SD

There is a few options but first I am hoping with your fuel pump replacement that you replaced the fuel filter if not do it first.
next have you checked you throttle body idle speed control device... See below on diagnostics
The curb and fast idle speeds are controlled by the Engine Control Assembly (ECA) and the Idle Speed Control Bypass Air Valve (ISC-BPA) . The ISC-BPA valve is not adjustable. A large increase or decrease in closed plate airflow from the calibrated level will not allow this device to control the speed.
The idle speed setting procedure has been revised considerably to reflect the expanded application of the Self-Test idle speed options and because the throttle body incorporates an orifice in the throttle plate to control idle airflow as part of the sludge tolerant design.


Throttle bodies with sludge tolerant design are clearly 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 (TPS 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 ISC-BPA 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 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 service output codes have been resolved.

STEP 1
With the engine OFF, connect a tachometer, according to manufacturer's instructions. Disconnect the negative (-) terminal of the battery for 5 minutes, then reconnect it.
STEP 2
START the engine and let 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 is not idling properly, turn the engine OFF, and proceed with this procedure.
STEP 4
Disconnect Idle Speed Control Air Bypass Solenoid.
STEP 5
START and RUN the engine at 2500 rpm for 30 seconds.
STEP 6
Place the transmission in PARK (A/T), or NEUTRAL (M/T).
STEP 7
Using a tachometer, verify the idle speed is at 650 +/-150 rpm.



NOTE: A plug in the throttle body orifice will decrease idle rpm. Where as an orifice without a plug will increase idle rpm. Orifice plugs and installation tools are available in service kit # FOPZ-9F652-A.

RPM TOO LOW

1. DO NOT clean the throttle body, check the plate orifice plug.

• If there is no plug, turn the screw clockwise to the desired rpm.
• If there is a plug from previous service, remove the plug, then adjust the screw in either direction as required. Screw must be in contact with the lever pad after adjustment.

RPM TOO HIGH

1. Turn the engine OFF.
2. Disconnect air cleaner hose.
3. Temporarily block the orifice in the throttle plate with tape. If the orifice already has a plug from previous service proceed to Step (e).
4. RESTART the engine. Check the idle speed, using a tachometer. NOTE: On vehicles with Mass Air Flow Sensors, reconnect the air intake duct hose prior to rechecking the rpm. If the engine stalls, crack open the throttle plate stop screw, but DO NOT over adjust.
5. If rpm continues to be fast, perform KOEO Self-Test.

• If TPS output code is within range, remove tape from throttle body and check for other possible causes.
• If TPS output is out of range, adjust screw for proper TPS code. Lever must be in contact with the screw.
• If rpm is still fast, terminate the procedure and check for other possible causes.

1. If rpm drops to 650 rpm or lower, or the engine stalls, turn the engine OFF, disconnect the air cleaner hose, and remove the tape from throttle plate.
2. Install an orifice plug with proper color code according to the throttle plate orifice size.
3. Reconnect the air cleaner hose. START the engine, and check the idle rpm using a tachometer. Turn the throttle plate stop screw clockwise until an idle speed of 650 +/- 25 rpm is achieved. NOTE: DO NOT turn the plate stop screw counterclockwise. This may cause the throttle plate to stick at idle.

STEP 8
Run the KOEO Self-Test for proper TPS code output.
STEP 9
Reconnect the Idle Speed Control Air Bypass Solenoid. Verify the throttle is not sticking in the bore, and the linkage is not preventing throttle from closing.
STEP 10
START the engine and idle for two minutes. Goose the accelerator and let the engine return to idle. Lightly depress and release the accelerator, then let engine idle.

PROCEDURES FOR PLUG INSTALLATION

STEP 1
Remove air inlet tube(s) from throttle body.
STEP 2
Select the proper color plug by using the Go/No-Go gauge pegs, included in the service kit (FOPZ-9F652-A).
STEP 3
Starting with the largest diameter gauge peg, attempt to insert through the throttle plate orifice.
STEP 4
If the gauge peg goes through the orifice, use the corresponding color plug.
If the gauge peg does not go through, proceed with the next smaller gauge peg for Go/No-Go Test.
NOTE: It is important that the largest Go/No-Go combination is used to determine the proper plug size.
STEP 5
If the smallest gauge peg does not go through the orifice, use the reamer bit and handle included with the service kit to enlarge the plate orifice. Wipe bearing grease on both sides of the plate orifice and on the reamer bit to hold the brass chips. After reaming, wipe plate clean and then return to Step 3 to determine the proper plug size.
STEP 6
Using the installation tool from the service kit, push the plug into the orifice until bottoming out at the throttle plate.
STEP 7
Open and snap closed the throttle several times to verify proper plug retention.
STEP 8
Reconnect the air inlet tube(s).
STEP 9
Reset idle rpm per engine requirement using the throttle plate stop screw.


Hope this helps

There could be several issues causing this problem. For one, I assume you meant 2000 rpm, not 20000 as the engine would have expired before reaching that number.

Checking the computer codes on this would be the safe thing to do as the Throttle Position Sensor could have failed or is sending the incorrect information to the ECU. Another possible issue to look for is a failure of the throttle return, if memory serves there should be a spring on the backside of the throttle body. If the spring is broken or missing, this could leave the throttle open enough to increase the rpm. I would also check the throttle body/throttle blade for dirt. Normally a dirty blade results in a decrease of rpm but it might be possible that it is sticking and not closing as it should. There are special throttle body cleaners available - do not use carb or brake cleaner as they could damage the throttle body. Let me know if any of the above helps.

idle air control valve issue, timing is advanced too far, or your throttle needs adjusted at the throttle body going into the intake where your throttle cable connects to throttle body.

it smoths out because you can't here the miss check fuel pressure and check for vachum leaks and build up on throttle plate.