Reduced engine power without cel

[travstick]

bad/ loose cable at gas peddle , throttle body controller actuator or loose cable at the throttle body

It's drive by wire

 

[travstick]

Check ltft against stft and report back. Mine did this when I developed a vacuum leak in my intake manifold.

What should the numbers be? Do this at idle or try to see what they are when it goes into reduced power? I normally work on all my vehicles and I know what long and short fuel trim is, but I don't really know much about using scan tool other than the typical check codes stuff

 

[travstick]

And thank you for your reply, I really appreciate any and all help I can get.....

 

[travstick]

I just had the same problem with my 03 Tahoe. I replaced the TCM and the TPS and neither fixed the problem completely. I had to replace the throttle body. The drive motor for the throttle body was going bad causing the throttle blade to flutter at idle which caused rough idle and reduced engine power. I however got a code.

I've been thinking throttle body but you know how throwing money at a problem is......I can make the "rep" happen sometimes with it still in park by just blipping the throttle and it seems to me like it takes too long to idle down after it's been rev'd up. Like maybe the throttle body is too slow or is this normal?

 

[wjburken]

Like maybe the throttle body is too slow or is this normal?

If there is a discrepancy between the accelerator position sensor and the throttle position sensor, it can cause an issue resulting in a reduced power condition.

 

[Fless]

I've been thinking throttle body but you know how throwing money at a problem is......I can make the "rep" happen sometimes with it still in park by just blipping the throttle and it seems to me like it takes too long to idle down after it's been rev'd up. Like maybe the throttle body is too slow or is this normal?

The behavior noted in that post leads me to believe the idle air control (IAC) isn't able to manage the airflow at idle. Classic signs of a dirty throttle body butterfly that won't close all the way. Suggest you clean it with throttle body cleaner and see if that does anything for your issue.

As also noted by @wjburken a discrepancy between those two sensors can wreak havoc. If you can graph the movement of the accelerator position sensor and the throttle position sensor on the throttle body, you should be able to see any variations between them, or a dropout in either one. One thing to check while you're poking around the TB are the wires to the sensor; inspect them carefully for broken or compromised wires within about a foot or so of the TB. Sometimes they break underneath the insulation.

 

[BG1988]

It's drive by wire

No it's not 2012 is electronic throttle body and e-gas pedal , as it has been electronic since 2004 model year...

most likely if you have all ready replaced the throttle body sensor the gas peddle sensor is broken..


try wiggling the pedal around see if it does it still


check with the OBD2 reader with live data the inverse and outverse have to match
No match = REP on the display


GM GENUINE PArt 23362231

 

[wjburken]

No it's not 2012 is electronic throttle body and e-gas pedal , as it has been electronic since 2004 model year...

That’s the definition of “drive by wire” vs “drive by cable”. The throttle gets its command through a wire that powers its actuator vs a cable that is physically connected to the pedal.

 

[travstick]

The behavior noted in that post leads me to believe the idle air control (IAC) isn't able to manage the airflow at idle. Classic signs of a dirty throttle body butterfly that won't close all the way. Suggest you clean it with throttle body cleaner and see if that does anything for your issue.

As also noted by @wjburken a discrepancy between those two sensors can wreak havoc. If you can graph the movement of the accelerator position sensor and the throttle position sensor on the throttle body, you should be able to see any variations between them, or a dropout in either one. One thing to check while you're poking around the TB are the wires to the sensor; inspect them carefully for broken or compromised wires within about a foot or so of the TB. Sometimes they break underneath the insulation.

I cleaned the throttle body when I replaced the tps, I checked the wires at the plug but will check then further away from the tps.

 

[travstick]

Check ltft against stft and report back. Mine did this when I developed a vacuum leak in my intake manifold.

I'm not sure what I'm looking for, what would be a sign of vacuum leak?