"Reduced engine power"

[chadfranks]

Afternoon. So I dug into this and removed the ground (black with white) off the pass side block. Re-grounded it to a good know ground but in the beginning I noticed when turning the key on the butterfly in the throttle body is fluttering and making a rattling noise with the engine off and also with the engine idling it make the same noise. Never noticed that before. I'm wondering if the actuator of the throttle body is faulty. Like I said it was a new throttle body replaced in August of 23. Anyone have an idea?

I am in the exact place you are, have you figured anything out? With the fluttering I suspected either ECM, or TAM, Or a ground, I've replaced both and ran new grounds as others have to the ecm, to the back of the engine, everywhere, I have ohmed out the wires from the TAM to the pigtail to the throttle body and shook the wires and harness while ohmed out and saw no issues, in the wiring but I still want to change the wiring harness because it is the only thing I can see, Unless the alternator is causing noise, or the battery negative isn't actually connected anymore in the molded connector, it has a new throttle body, on my diagnostics, when it throws the code, the ecm really isn't seeing any voltage on the wires from the sensor and the fluttering means there's some type of connection issue, it has no problem reporting the voltage from the gas pedal so ecm to tac connections should be fine, the only thing I can think is to change the wiring harness which I did get caught under the intake on this fix when I changed fuel injectors and plugs and wires. GM Parts Giant doesn't show the harness part number because is is discontinued so I'm not 100% where to buy one from, amazon review on a $75 one showed they had to repin some of the purple connector on the ecm, let me know what you got going

 

[89Suburban]

I am in the exact place you are, have you figured anything out? With the fluttering I suspected either ECM, or TAM, Or a ground, I've replaced both and ran new grounds as others have to the ecm, to the back of the engine, everywhere, I have ohmed out the wires from the TAM to the pigtail to the throttle body and shook the wires and harness while ohmed out and saw no issues, in the wiring but I still want to change the wiring harness because it is the only thing I can see, Unless the alternator is causing noise, or the battery negative isn't actually connected anymore in the molded connector, it has a new throttle body, on my diagnostics, when it throws the code, the ecm really isn't seeing any voltage on the wires from the sensor and the fluttering means there's some type of connection issue, it has no problem reporting the voltage from the gas pedal so ecm to tac connections should be fine, the only thing I can think is to change the wiring harness which I did get caught under the intake on this fix when I changed fuel injectors and plugs and wires. GM Parts Giant doesn't show the harness part number because is is discontinued so I'm not 100% where to buy one from, amazon review on a $75 one showed they had to repin some of the purple connector on the ecm, let me know what you got going

@915_Tahoe is there a part number for the mentioned harness sir?