Any silverado 4.8 vortec owners here?

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11/8/2018 7:35 PM

2012 silverado 1500. The truck has a terrible throttle delay, about 1.5 seconds from the time you put your foot down till it does anything. Wear isnt an issue, it only has 12,500 miles on it, 100% stock Is there anything that can be done to fix it? Tune?

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2009 RMZ 250 (sold)
2004 LTZ 400
#nukethequads

11/9/2018 3:43 AM

If you have access to a good obd2 scanner you can try to re-calibrate the tps (throttle position sensor ) with the gas pedal and see if there is an improvement.

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11/9/2018 6:57 AM

Cheap
Hardly
Efficient
Virtually
Runs
On
Luck
Every
Time



Sorry, I had too!

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11/10/2018 12:33 PM

I've seen on a few of the older Vortecs that the backside of butterfly valve on the throttle body can get gummed up pretty bad, which can cause an assortment of issues. Pull the intake tube between the air filter housing and the throttle body. Manually open it up, and with some carb clean and a rag wipe it any soot or shmutz in there. Reassemble and try it out.

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11/10/2018 12:48 PM

Marty1028 wrote:

2012 silverado 1500. The truck has a terrible throttle delay, about 1.5 seconds from the time you put your foot down till it does anything. Wear isnt an issue, it only has 12,500 miles on it, 100% stock Is there anything that can be done to fix it? Tune?

If it's running well and it's just a delay, not cutting out, then it's likely to be the drive-by-wire system. There are tuners out there that can minimize the lag a bit.

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11/10/2018 6:08 PM

You need access to OBD2 scan tool that will give you data PID's

See what the TPS Voltage is at Idle , then see what the voltage is when you start to depress the throttle when the RPM goes up.

static Idle Voltage I think is .5v-1v the PCM know you gave it a command to be off idle at 1.25v the closer to .5v the slower it will react and the closer to 1.25v the faster it will react.

You might just have a TPS that has a dead spot and if someone has put an aftermarket on in it at sometime start there and get an OEM one.

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11/11/2018 4:03 PM

500guy wrote:

You need access to OBD2 scan tool that will give you data PID's

See what the TPS Voltage is at Idle , then see what the voltage is when you start to depress the throttle when the RPM goes up.

static Idle Voltage I think is .5v-1v the PCM know you gave it a command to be off idle at 1.25v the closer to .5v the slower it will react and the closer to 1.25v the faster it will react.

You might just have a TPS that has a dead spot and if someone has put an aftermarket on in it at sometime start there and get an OEM one.

Shes 100% bone stock. Runs very well and is barely broke in. Only 12,000 miles on it of very light driving from 2012 to now. It was my grandpas truck but once he turned 85 they jacked the insurance rates on him so they got rid of it. Anyway ill see if a buddy of mine has a tuner. Luckily i have a good bosch obd scanner.

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2009 RMZ 250 (sold)
2004 LTZ 400
#nukethequads

11/11/2018 10:15 PM

Found this



Document ID: 3940199
#PIP4112P: Normal Characteristic - Sag Or Hesitation O
n
Acceleration - (Jun 26, 2014)
Subject: Normal Characteristic - Sag Or Hesitation
On Acceleration
Models: 2008-2012 Buick Enclave
2010-2011 Buick LaCrosse MH7
2010-2013 Buick LaCrosse MH2, MH4
2011 Buick Regal MH7
2006-2009 Cadillac XLR, XLR-V
2006-2011 Cadillac STS, STS-V
2007-2012 Cadillac SRX
2007-2015 Cadillac Escalade, Escalade EXT, Escalade
ESV
2008-2015 Cadillac CTS
2013-2015 Cadillac ATS
2006-2015 Chevrolet Corvette
2007-2013 Chevrolet Avalanche
2007-2015 Chevrolet Silverado, Suburban, Tahoe
2008-2011 Chevrolet Malibu MH8
2008-2013 Chevrolet Malibu MH2
2008-2012 Chevrolet Equinox MH2, MH4
2009-2011 Chevrolet Equinox MHC, MH7
2009-2012 Chevrolet Traverse
2011 Chevrolet Cruze
2012 Chevrolet Cruze MH9
2010-2015 Chevrolet Camaro, Express
2011-2015 Chevrolet Caprice
2012 Chevrolet Captiva Sport MHJ, MHK
2012 Orlando
2012 Chevrolet Sonic MH9
2012-2013 Chevrolet Impala
2014 Chevrolet SS
2007-2015 GMC Sierra, Yukon, Yukon XL
2008-2012 GMC Acadia
2010-2012 GMC Terrain MH2, MH7
2010-2011 GMC Terrain MHC, MH7
2010-2015 GMC Savana
2008-2011 HUMMER H2
2007-2010 Pontiac G6 MH2
2009-2010 Pontiac G6 MH8
2008-2009 Pontiac G8
2008-2009 Pontiac Torrent MH2, MH4
2007-2009 Saturn Aura MH2
2009 Saturn Aura MH8
2008-2010 Saturn Outlook, Vue MH2, MH4
© 2014 General Motors. All rights reserved.
Page
1
of
2
Document ID: 3940199
7/
7/
2014
https://gsi.ext.gm.com/gsi/showDoc.do?docSyskey=3940199&from=nb
Equipped With a Gasoline Engine and Automatic Transm
ission
This PI was superseded to update Models and Model Ye
ars. Please discard PIP4112N.
The following diagnosis might be helpful if the vehi
cle exhibits the symptom(s) described in this PI.
Condition/Concern
Some customers may comment on a sag or hesitation wh
en accelerating under the following
conditions:
When coasting at low speeds of less than 15 miles p
er hour with a closed throttle and then
aggressively applying the throttle. Examples of this
maneuver include a rolling stop or a lane
change maneuver. In this type of maneuver, even thou
gh the accelerator is applied aggressively,
the throttle blade is opened slowly for up to 0.7 se
conds to help minimize drive-line lash and
clunking.
Also in a vehicle equipped with a six speed automati
c transmission when making a hard, complete
stop with a closed throttle, immediately followed by
an aggressive throttle opening the
transmission down-shifts may not be completed by th
e time the throttle is opened. As a result
approximately 0.5 seconds of ′′zero′′ torque may be co
mmanded to allow the shift to first gear to
occur.
Recommendation/Instructions
Both of the above conditions are a result of Torque
Management and both of these conditions
should be considered normal and no repairs should b
e attempted.
Please follow this diagnostic or repair process tho
roughly and complete each step. If the condition
exhibited is resolved without completing every step,
the remaining steps do not need to be
performed.
Please follow this diagnostic or repair process tho
roughly and complete each step. If the condition
exhibited is resolved without completing every step,
the remaining steps do not need to be
performed.
GM bulletins are intended for use by professional te
chnicians, NOT a "do-it-yourselfer". They are writ
ten to inform these
technicians of conditions that may occur on some ve
hicles, or to provide information that could assist
in the proper service of a
vehicle. Properly trained technicians have the equ
ipment, tools, safety instructions, and know-how to
do a job properly and
safely. If a condition is described, DO NOT assume
that the bulletin applies to your vehicle, or that y
our vehicle will have that
condition. See your GM dealer for information on wh
ether your vehicle may benefit from the information.
WE SUPPORT
VOLUNTARY
TECHNICIAN
CERTIFICATION
Page
2
of
2
Document ID: 3940199
7/
7/
2014
https://gsi.ext.gm.com/gsi/showDoc.do?docSyskey=3940199&from=nb

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11/12/2018 4:42 AM

my 2016 does the same thing. always has a weird delay.

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11/12/2018 6:11 AM

Dirtydeeds wrote:

Cheap
Hardly
Efficient
Virtually
Runs
On
Luck
Every
Time



Sorry, I had too!

Cracked
Head
Every
Valve
Rattles
Oil
Leaks
Every
Time



Had to help out, haha.

Seriously though, my 2010 I had did this same thing.
Put your foot thru the floor to get out in front and then there is a dramatic pause to where you can't drive a nail up your ass with a hammer, then it kicks in just in the Knick of time, haha.

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