"Reduced engine power"

kayakfish247 said:

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?

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chadfranks said:

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

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89Suburban said:

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

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89Suburban said:

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

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chadfranks said:

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

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89Suburban said:

I was referring to a complete harness not just the pigtail.

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4L60E DBW DAC095, now it has the ECM connectors as Blue and Green, I think that is the biggest difference to look our for, My Tahoe is a LT 5.3L Flex fuel, but when I first suspected the ECM, I thought I'd just swap with my truck and that wasn't possible, it's keyed connectors to the ECM are Red and Blue​

89Suburban said:

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

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915_Tahoe said:

I would need the VIN#

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chadfranks said:

Hey, I think I finally have mine fixed, my events were had an unrelated issue involved disconnecting the Throttle connectors, an issue was created or uncovered there. When suspecting bad sensor in the Throttle body, replaced the throttle body, it would flutter when key went into second position, like it could not control the throttle body or needed to retune, after seeing there was no voltage back from sensor, I knew I had a connector problem, fixed that but still had an issue, I fixed grounds, swapped computer, swapped tbc module, those did not fix so I returned. Ultimately decided to put the original throttle back on because I had fixed the connector and saw that the original unit was fine, i just had a problem in that pigtail

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