Impala 2001 Throttle Position Sensor!

2001 CHEVROLET IMPALA
175,000 MILES
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VWNS21
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I have Impala 2001 it run great, I go somewhere and come back about 2 - 10 minutes. Hard to start then fine. sometime at the stop light it stalls. it started with it not starting right away. In the morning I start it, starts right away. then come back 5 -10 minutes, it did not start right away, it took about 3 - 5 seconds.then start. I never had to give it gas on the gas paddle. now it do! I talk to my friend and he said it could be the Throttle Position Sensor! I have a Diagnostic tool made by innova, it is 1003e, can obd2. it say no codes, no problems!
Nov 29, 2011 at 8:39 PM
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RIVERMIKERAT
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The Innova scantool will only read codes that set the CEL. These are called hard codes. The TPS may have set a soft code, one that doesn't set the CEL. Take it to a shop or parts store that will read all codes for free.
Nov 29, 2011 at 8:58 PM
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VWNS21
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So you don't think it is the Throttle Position Sensor?
I will get a fuel pressure gauge and check the fuel pressure!
do you have any other suggestions.
Do you know of any store that will read all codes for free?
Nov 29, 2011 at 10:38 PM
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RIVERMIKERAT
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In California, Pep Boys and Autozone used to, but a new law was passed recently making it illegal. There are numerous small repair shops that will do it for free. Aamco advertises that they scan for codes for free, also.

With a fuel injected vehicle, the throttle pedal doesn't control the amount of fuel entering the engine, it controls the amount of air. So, if you have to move the pedal around while starting, this tells me the engine is getting too much fuel during the startup process. This could be a leaking injector, or the computer receiving incorrect signals causing it to give more fuel, or processing the signals incorrectly. This means there is a possibility the problem is the throttle position sensor, but it could also be a bad manifold absolute pressure sensor/mass airflow sensor, oxygen sensor, or other related sensors.
Nov 30, 2011 at 3:14 AM