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Discussion Starter #1
I have a question for you guys.. My LBZ has always had very fast hard shifts at full throttle on any tune from duramax tuner. Recently it will hesitate really bad under the max hp tune between shifts. I know this can be a bad fuel filter like I have had before but I replaced it with no help. The truck seems to smoke more then ever also. I bumped up my lift pump pressure and made no diff. Should I get a lift pump and fuel rail gauge? or can the fuel rail pressure be checked through the scan tool of efi? Also what is optimal Fuel rail pressure at fuel throttle with stock motor?

Thanks for helping in advance.
 

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I have a question for you guys.. My LBZ has always had very fast hard shifts at full throttle on any tune from duramax tuner. Recently it will hesitate really bad under the max hp tune between shifts. I know this can be a bad fuel filter like I have had before but I replaced it with no help. The truck seems to smoke more then ever also. I bumped up my lift pump pressure and made no diff. Should I get a lift pump and fuel rail gauge? or can the fuel rail pressure be checked through the scan tool of efi? Also what is optimal Fuel rail pressure at fuel throttle with stock motor?

Thanks for helping in advance.
Oh no! Sorry to hear about your vehicle. If you want, I can locate a dealer for you and they will be your best source for information. Please keep me posted!

Joey, GM Customer Service
 

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Discussion Starter #4
check your fprv. does it throw any codes?
its already shimmed and no codes. Nothings different then when it was shifting hard thats whats weird.
 

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Discussion Starter #5
If you click on my youtube chanel and watch videos from Pittburgh raceway about a year ago compared to my run at Mercer I just uploaded you can see the difference plain as day in the shift.
 

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Discussion Starter #6
nothin>>>?
 

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Discussion Starter #7
I installed FRP gauge yesterday and at full throttle high rpm its steady at 26,000 psi. doesnt drop at all when shift hesitates.. Lift pump gauge not hooked up yet.
 
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