RPM/Acceleration Issue
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Driver School Candidate
Joined: Oct 2014
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From: new york
Instructor
Joined: Feb 2009
Posts: 1,199
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From: Ontario, Canada
Low idle, jumpy highway performance, and lack of power when pedal is fully depressed is exactly what would happen when the throttle position sensor is not calibrated correctly.
Did anyone ever clean the throttle body, and if so, did they do it by hand and push the flap open, or did they have someone turn the ignition to ON and step on the accelerator to open the throttle plate? Pushing it by hand is not recommended because it can throw off the calibration of the throttle position sensor.
Check your throttle position sensor - you'll need a handheld tester or Techstream. Turn the ignition to ON, and do not touch the accelerator pedal. The throttle valve opening percentage (THROTTLE POS) in the live data screen should read between 14.4 and 16%. I suspect yours will read below 14.4. If so, follow the instructions at www.lexls.com/tutorials/EFI/tps.html to recalibrate.
While you're at it, check your accelerator pedal position sensor - should read 0.6 - 1.0 V. Also, if you have a multimeter, check the throttle body assembly - resistance across terminals 1 and 2 should be 0.3-100 Ohms at 20C, resistance across terminals 3 and 5 should be 1.2 - 3.2 kOhms. If those items read outside of spec, replace the part.
If TPS is good, I'd check all vacuum hoses (including the vacuum switching valve on the side of the airbox) for leaks and loose connections.
Did anyone ever clean the throttle body, and if so, did they do it by hand and push the flap open, or did they have someone turn the ignition to ON and step on the accelerator to open the throttle plate? Pushing it by hand is not recommended because it can throw off the calibration of the throttle position sensor.
Check your throttle position sensor - you'll need a handheld tester or Techstream. Turn the ignition to ON, and do not touch the accelerator pedal. The throttle valve opening percentage (THROTTLE POS) in the live data screen should read between 14.4 and 16%. I suspect yours will read below 14.4. If so, follow the instructions at www.lexls.com/tutorials/EFI/tps.html to recalibrate.
While you're at it, check your accelerator pedal position sensor - should read 0.6 - 1.0 V. Also, if you have a multimeter, check the throttle body assembly - resistance across terminals 1 and 2 should be 0.3-100 Ohms at 20C, resistance across terminals 3 and 5 should be 1.2 - 3.2 kOhms. If those items read outside of spec, replace the part.
If TPS is good, I'd check all vacuum hoses (including the vacuum switching valve on the side of the airbox) for leaks and loose connections.
Thread Starter
Driver School Candidate
Joined: Oct 2014
Posts: 16
Likes: 0
From: new york
Low idle, jumpy highway performance, and lack of power when pedal is fully depressed is exactly what would happen when the throttle position sensor is not calibrated correctly.
Did anyone ever clean the throttle body, and if so, did they do it by hand and push the flap open, or did they have someone turn the ignition to ON and step on the accelerator to open the throttle plate? Pushing it by hand is not recommended because it can throw off the calibration of the throttle position sensor.
Check your throttle position sensor - you'll need a handheld tester or Techstream. Turn the ignition to ON, and do not touch the accelerator pedal. The throttle valve opening percentage (THROTTLE POS) in the live data screen should read between 14.4 and 16%. I suspect yours will read below 14.4. If so, follow the instructions at www.lexls.com/tutorials/EFI/tps.html to recalibrate.
While you're at it, check your accelerator pedal position sensor - should read 0.6 - 1.0 V. Also, if you have a multimeter, check the throttle body assembly - resistance across terminals 1 and 2 should be 0.3-100 Ohms at 20C, resistance across terminals 3 and 5 should be 1.2 - 3.2 kOhms. If those items read outside of spec, replace the part.
If TPS is good, I'd check all vacuum hoses (including the vacuum switching valve on the side of the airbox) for leaks and loose connections.
Did anyone ever clean the throttle body, and if so, did they do it by hand and push the flap open, or did they have someone turn the ignition to ON and step on the accelerator to open the throttle plate? Pushing it by hand is not recommended because it can throw off the calibration of the throttle position sensor.
Check your throttle position sensor - you'll need a handheld tester or Techstream. Turn the ignition to ON, and do not touch the accelerator pedal. The throttle valve opening percentage (THROTTLE POS) in the live data screen should read between 14.4 and 16%. I suspect yours will read below 14.4. If so, follow the instructions at www.lexls.com/tutorials/EFI/tps.html to recalibrate.
While you're at it, check your accelerator pedal position sensor - should read 0.6 - 1.0 V. Also, if you have a multimeter, check the throttle body assembly - resistance across terminals 1 and 2 should be 0.3-100 Ohms at 20C, resistance across terminals 3 and 5 should be 1.2 - 3.2 kOhms. If those items read outside of spec, replace the part.
If TPS is good, I'd check all vacuum hoses (including the vacuum switching valve on the side of the airbox) for leaks and loose connections.
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