High idle around 1300-1500, around 1000 when in gear. Got the car from my grandmother who passed away last year. Only 44k on it. Scan showed stored code for low tps circuit. It started to act up on her before she passed. I think her mechanic replaced the tps.

live data on scanner showed Throttle position % anywhere from 1.6-9.0. Cleared the code, disconnected negative. Car ran perfect for about 10 miles. So I replaced the tps with junk from AutoZone. Worked for about the same amount of time, scanner showing 0.8-28% open when it started to act up. Checked for vacuum leaks all good, pulled IAC cleaned, cleaned throttle body, cleaned PCV, cleaned MAF. Disconnected cruise cable, no corrosion on wires.

when I had the IAC out it was about half way, I manually pushed it in to full open then key on engine of and piston extended fully the reset to halfway. I guess that’* normal. Just trying to give as much info as I can. Any ideas as to what is going on? Thanks in advance guys and girls

On the scan tool KOEO what does the TPS do from no pedal to WOT. Percent or volts.

it shows percentage

When I replaced it, it would show 0% at close and 100% WOT

I think it should be about 7% at idle and no throttle.

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Home >> Buick >> 2003 >> Century V6-3.1L VIN J >> Repair and Diagnosis >> Powertrain Management >> Sensors and Switches - Powertrain Management >> Sensors and Switches - Fuel Delivery and Air Induction >> Throttle Position Sensor

Throttle Position Sensor

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First off, thank you for the link to the repair manual. Second, when I’m driving with live data on the scan tool, it will show the tps all over the place with foot off the gas. Like 2.4-28%, now I know I could have just gotten a bunk sensor from auto zone, I will go with one spec once I can pin point that it’* the tps. Another thing is I can unplug the tps and on the scan tool it still shows a percentage value bouncing around. Could that possibly be a PCM issue? If the throttle cable isn’t physically opening the butterfly how are the rpms fluctuating so much? That’* why I’m leaning more towards the IAC valve, the p121 wasnt lighting the CEL, I only saw it stored and pending when I hooked the scan tool up a few days ago when I got the car.

Check the wiring at the sensor. From the manual. Go to diagrams . What do you get for values?

Throttle Position Sensor

• Diagrams

Meters out good, ~.4 closed and ~4.5 WOT. Smooth accel and decel on the meter

here is all the live data my tool shows. Some are running and warmed up some are KOEO

I'm not convinced that there'* not a vacuum leak.

Also, what was the TPS code that you mentioned from Post #1?

Are there any codes stored in there now?

What does the tach read when the key is turned on and the engine is stopped?