What is the reflash that everyone is talking about and claims that it makes the truck smoother and more responsive? I called GM Canada and they said that they never heard of it. I would like some more info and maybe a reference number or something so that I can get this done.

When I went to one of the dealers in the area, they weren't aware of it either. I told them that I was having low idle surges and that some people have had it fixed by a reflash of the PCM. Once he gathered my data, from my PCM, and looked at it on line, he saw the reflash that was noted. He performed the reflash and the truck did seem peppier and quieter. No more bucking like bronco when idling around 1k.

just do a search for reflash or pip3129 and you will find all the info.. here is the document. the latest one is PIP3129B


04 6.6 LLY Smoke , Fuel Knock , Surging and High Injector Balance Rates - kw white black idle surge rough noise accelerate P0300 P0301 P0302 P0303 P0304 P0305 P0306 P0307 P0308 miss misfire SES DTC #PIP3129 - (Sep 10, 2004)[

04 6.6 LLY Smoke, Fuel Knock, Surging, and High Injector Balance Rates
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The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

Condition/Concern:

Customer concern may be a low speed surge (8 to 10 mph or near 1000 RPM), acceleration fuel knock noise at 1500 to 1800 RPM, rough idle, white smoke at idle, or high positive injector balance rates.

Recommendation/Instructions:

High positive injector balance rates (over +4.0 in park or +6.0 in drive) may be causing white smoke at idle or while driving.

Document all injector cylinder balance rates at the beginning of the diagnosis.

There is an updated calibration to address the white smoke, high positive balance rates, idle surge, and a fuel knock noise at or near 1500 to 1800 RPM.

Install the updated calibration and evaluate the smoking, high injector balance rates, idle surge, and fuel knock noises.

If there is still a mechanical concern with an injector, and balance rates are still over the SI specification of +4.0 in park or +6.0 in drive, replace only the effected injector.


NOTE: Before any injector replacements a large fuel sample should be taken from the fuel filter and checked for contaminants or poor quality.

Find another dealer quick!! I use the Medium Duty Service Center in Toronto and they had me in and out in 20 mins. No stupid questions.

Find another dealer quick!! I use the Medium Duty Service Center in Toronto and they had me in and out in 20 mins. No stupid questions. My brother-in-law who lives in Windsor, went to the same place. He said the same thing about them.