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Topic: 1996 LT-4 idles rough and stalls after 10 seconds.

in Forum: C4 Engines


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1996 LT-4 idles rough and stalls after 10 seconds. (1/6)
 6/11/23 10:37am
Anthony DiChario
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Vette(s):
1996 LT-4 manual transmission with ProCharger 6 lbs boost and NOS


Joined: 6/11/2023
Posts: 1

1996 LT-4 manual transmission starts and idles very rough for a few seconds then smooths out and increases RPMs for a few more seconds total run time about 10 seconds then shuts off.  Things already replaced: fuel filter, fuel pressure regulator, spark plugs, fuel pump, and fuel injectors. Dashboard shows service ASR and check engine light is on. Any ideas where to look from here?

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Re: 1996 LT-4 idles rough and stalls after 10 seconds. (2/6)
 6/12/23 9:37pm
BooBoo421!
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Middleville, MI - USA

Vette(s):
Bought my Vette!👍😎


Joined: 12/11/2022
Posts: 24

Hi, I am not a fix it kind of giy but you have troubleshooter a lot already.  Maybe O2 sensor(s) or plugged line somewhere.

God bless,

BooBoo421!



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Joseph Booher

Re: 1996 LT-4 idles rough and stalls after 10 seconds. (3/6)
 6/15/23 12:33am
Corveddie
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Beacon, NY - USA

Vette(s):
1994 convertible, arctic white, black top and interior. LT1 auto.


Joined: 11/29/2009
Posts: 43

Maybe consult with Gordon Killibrew?

http://www.corvettebuyers.com/killebrew/index.html

CorvEddie

Re: 1996 LT-4 idles rough and stalls after 10 seconds. (4/6)
 6/28/23 12:34pm
Phat98
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Crystal Springs, MS - USA

Vette(s):
1973 Mille Miglia Red LS5 1981 Claret Red 1982 White 1985 Silver Metallic 1988 Yellow 1993 Torch Red ZR-1 1994 Torch Red Coupe LT1 1996 Dark Purple Metallic LT4 2000 Torch Red 2001 Light Pewter 2003 Z06 Millennium Yellow 2009 Atomic Orange


Joined: 7/29/2011
Posts: 33

Got a buddy with a Tech2 or even a OBD2 scanner? You should be able to pull some codes to get you started and you can log your startup to narrow down what's causing the issue.

My first guess would be MAF or throttle body related, IAC or TPS may need to be adjusted. Have you isolated any of your add-ons that may be causing the problem?

Just spit-ballin' here...



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1973 Mille Miglia Red LS5 - SOLD
1981 Dark Claret Metallic - SOLD
1982 White
94 Torch Red LT1
96 Dark Purple Metallic LT4
02 Black Convertible - SOLD
03 Millennium Yellow Z06
09 Atomic Orange Z51
 
Re: 1996 LT-4 idles rough and stalls after 10 seconds. (5/6)
 7/12/23 1:40pm
767flyer
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Rutherfordton, NC - USA

Vette(s):
1993 Triple White Convertible 2016 3LT Coupe, torch red


Joined: 8/13/2013
Posts: 10

Before just replacing more expensive parts, I would suggest checking for vacuum leaks.  Are your hoses 20+ years old? Vacuum leaks are a PITA to find sometimes but can cause lots of idle related issues. Spend some time looking carefully and it may very well solve your idle problems. 



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Re: 1996 LT-4 idles rough and stalls after 10 seconds. (6/6)
 6/14/24 5:57pm
John Piluso
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Joined: 6/2/2024
Posts: 1

I have a similar problem but I don't stall runs rough on the low idle but doesn't stall. SES light comes on the low idle mostly, once cruising speed on the highway SES goes off. I have a code of 44 with the OBD1 scanner and that is a lean code left bank. 

I have changed the following: fuel filter, fuel pressure reg, fuel pump, Fuel Injectors, Spark plugs, Throttle Pos sensor, EGR, EGR Control Valve Sensor, PCV, PCV Valve Hose, Vent Grommet for PCV Hose, Manifold Air Temp Sensor, Air Intake temp sensor, Ignition Coil, TPS sensor, Sent the ECM out to be checked and that was fine. I cleaned the throttle body and replaced the air filter. All of these items were original to the vehicle with 58k miles so I figured they should be changed and will help my cause. The Opti Spark and Spark plug wires are probably a winter project and don't think they are causing the problem. So with that said I think a smoke test is in order because it appears there are a lot of vacuum issues with the LT 1 corvette plus they are 30 years old. Any other recommendations. 



|UPDATED|6/14/2024 2:57:14 PM (AZT)|/UPDATED|
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