Symptoms for idle position sensor problems? - 2002 Chevrolet TrailBlazer

It could be the throttle position sensor, MAP Sensor, or Mass Airflow Sensor (MAF) Symptoms of Bad or Failing Mass Airflow Sensor YourMechanic Advice
Symptoms of Bad or Failing Throttle Position Sensor
Symptoms of Bad or Failing Manifold Absolute Pressure Sensor MAP Sensor...

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It seems like idle is too low. There should be a screw to turn and adjust idle speed.

Hello,

Do you have an engine light? Throwing a code?
Just does this at idle or when driving/acceleration?
Acting strange changing symptoms (E.G.--idle to acceleration to black smoke out exhaust, etc.)? Plenty of Gas in tank?

I am thinking: No engine light
Clog in fuel filter
intermittent fuel pump problem
A vehicle starting sensor (E.G.--Throttle Position Sensor (TPS))
Main computer
Engine Light: Pull Code
Sensor

I hope this helps.

that ,sorry is not a question, its a statement.
my wild guess? you have symtoms and are guessing?
post the symptoms, and we can do simple tests.
guessing will cost big money, why make the parts man rich.
symptoms, evidence, diagnosis, and solutions.
in that order.

That's a symptom of a vacuum leak or an air duct leak between the air filter box and throttle.

first thing that comes to mind would be the throttle positioning sensor, or the mass air flow intake sensor on the air intake hose assembly.Symptoms of a mass airflow intake sensor would be very poor acceleration or engine dying when gas pedal is mashed hard. Throttle positioning sensor can give you and irradical idle while sitting still. You might want to have a scan to diagnose the problem.

A bad throttle position sensor wouldn't cause those symptoms. Return it before you waste more money. Check the EGR valve to make sure it's fully closed at idle

There is no idle sensor on the 2000 Chevrolet Impala, according to my online resource.

But, there is the following that senses rpm of the engine and thus the idle speed when the Throttle Position Sensor is at 5% or the accelerator pedal is not depressed:

Crankshaft Position Sensor Operation Engine speed is a very important input to the Powertrain Control Module (PCM). Crankshaft speed and position are the basis for many calculations made by the computer. Crankshaft position values are transmitted to the computer by pickup coils also known as Permanent Magnet (P/M) generators, Hall Effect sensors or optical sensors. The Crankshaft Position Sensor (CKP) also known as engine speed sensor is typically located in proximity to the crankshaft.
In addition, the PCM uses the CKP sensor in conjunction with the camshaft position sensor to calculate and perform misfire diagnostics.
Related Symptoms

• A No Start / Intermittent Start condition - Can be caused by a faulty crankshaft position sensor due to loose connections, bad grounds, high resistance in the circuit, or opens in the circuit.
• Engine Misfire Diagnostic Trouble Codes

NOTE: Engine Mechanical conditions can also create the same or similar symptoms. (Don't overlook basic mechanical integrity).

The camshaft position sensor is on the rear cylinder head on the left end (the serpentine belt end of the engine - passenger side). It is a son-of-a gun to get at. When it is bad or the connector is intermittant or bad, the symptom will be irregular idle from 500 to 750 RPM or so.

There is a recall on the engine computer for this problem