1996 Lt1 Tps ........help?
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Joined: Sep 2005
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1996 Lt1 Tps ........help?
HAVE A 1996 LTI. When I let off the gas car still holds about 1200 to 1400 rpm. Idel dosent drop until i almost come to a stop. athis almost seems like the cruise control is on. I am thinking it's the tps, but dont want to buy on if its not it. Anyone have any ideas? Thanking you in advance. Ray 
Race Director
Joined: Dec 2006
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Back-probe the TPS with key on engine off. The output should move smoothly from almost zero to alsmot +5 volts DC as the throttle is moved from closed to open.
Inspect all vacuum lines. Inspect air ducts. Inspect IAC.
Inspect all vacuum lines. Inspect air ducts. Inspect IAC.
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
Sounds like it could just be the Idle Air Control (IAC) needing to be recalibrated.
Just before it started, have you done something that could have allowed or dislodged some dirt into the intake (e.g. changed air filter, cleaned TB or MAF) or gone through a really dusty area?
If so, a small bit of dirt could have hung-up the IAC.
Not sure about the 96 LT1, but for the 94 LT1, there is a simple way of recalibrating the IAC.
1. Before starting the car, depress the gas pedal slightly.
2. start the car, and immediately take your foot of the gas pedal.
3. Let the car idle for 5 SECONDS.
4. turn off the car for 10 SECONDS.
5. restart the car.
6. the PCM will readjust the IAC to the correct idle.
If this does not fix the problem, consider starting simple --
Consider cleaning the Throttle-Body and Mass Air Flow sensor.
use products specifically designed for both (e.g. CRC TB cleaner and CRC MAF cleaner) as more harsh cleaners can damage coatings or the sensor wire.
btw, no need to remove the TB, but do consider removing the IAC and cleaning its chamber.
Do prevent leakage of the cleaner out of the TB down onto the OPTI.
ALso, the car may act like it is 'flooded' after cleaning the TB, so be sure your battery is charged, just in case.
Thereafter, after the car runs a bit, try resetting the IAC again, it might then solve your problem.
Just before it started, have you done something that could have allowed or dislodged some dirt into the intake (e.g. changed air filter, cleaned TB or MAF) or gone through a really dusty area?
If so, a small bit of dirt could have hung-up the IAC.
Not sure about the 96 LT1, but for the 94 LT1, there is a simple way of recalibrating the IAC.
1. Before starting the car, depress the gas pedal slightly.
2. start the car, and immediately take your foot of the gas pedal.
3. Let the car idle for 5 SECONDS.
4. turn off the car for 10 SECONDS.
5. restart the car.
6. the PCM will readjust the IAC to the correct idle.
If this does not fix the problem, consider starting simple --
Consider cleaning the Throttle-Body and Mass Air Flow sensor.
use products specifically designed for both (e.g. CRC TB cleaner and CRC MAF cleaner) as more harsh cleaners can damage coatings or the sensor wire.
btw, no need to remove the TB, but do consider removing the IAC and cleaning its chamber.
Do prevent leakage of the cleaner out of the TB down onto the OPTI.
ALso, the car may act like it is 'flooded' after cleaning the TB, so be sure your battery is charged, just in case.
Thereafter, after the car runs a bit, try resetting the IAC again, it might then solve your problem.
Instructor
Joined: Dec 2007
Posts: 156
Likes: 0
From: Powhatan Virginia
Sounds like it could just be the Idle Air Control (IAC) needing to be recalibrated.
Just before it started, have you done something that could have allowed or dislodged some dirt into the intake (e.g. changed air filter, cleaned TB or MAF) or gone through a really dusty area?
If so, a small bit of dirt could have hung-up the IAC.
Not sure about the 96 LT1, but for the 94 LT1, there is a simple way of recalibrating the IAC.
1. Before starting the car, depress the gas pedal slightly.
2. start the car, and immediately take your foot of the gas pedal.
3. Let the car idle for 5 SECONDS.
4. turn off the car for 10 SECONDS.
5. restart the car.
6. the PCM will readjust the IAC to the correct idle.
If this does not fix the problem, consider starting simple --
Consider cleaning the Throttle-Body and Mass Air Flow sensor.
use products specifically designed for both (e.g. CRC TB cleaner and CRC MAF cleaner) as more harsh cleaners can damage coatings or the sensor wire.
btw, no need to remove the TB, but do consider removing the IAC and cleaning its chamber.
Do prevent leakage of the cleaner out of the TB down onto the OPTI.
ALso, the car may act like it is 'flooded' after cleaning the TB, so be sure your battery is charged, just in case.
Thereafter, after the car runs a bit, try resetting the IAC again, it might then solve your problem.
Just before it started, have you done something that could have allowed or dislodged some dirt into the intake (e.g. changed air filter, cleaned TB or MAF) or gone through a really dusty area?
If so, a small bit of dirt could have hung-up the IAC.
Not sure about the 96 LT1, but for the 94 LT1, there is a simple way of recalibrating the IAC.
1. Before starting the car, depress the gas pedal slightly.
2. start the car, and immediately take your foot of the gas pedal.
3. Let the car idle for 5 SECONDS.
4. turn off the car for 10 SECONDS.
5. restart the car.
6. the PCM will readjust the IAC to the correct idle.
If this does not fix the problem, consider starting simple --
Consider cleaning the Throttle-Body and Mass Air Flow sensor.
use products specifically designed for both (e.g. CRC TB cleaner and CRC MAF cleaner) as more harsh cleaners can damage coatings or the sensor wire.
btw, no need to remove the TB, but do consider removing the IAC and cleaning its chamber.
Do prevent leakage of the cleaner out of the TB down onto the OPTI.
ALso, the car may act like it is 'flooded' after cleaning the TB, so be sure your battery is charged, just in case.
Thereafter, after the car runs a bit, try resetting the IAC again, it might then solve your problem.
If this is something that started all on it's own AND not after another mod/repair --I'd guess dirty IAC valve.
