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Rough idle when first start up

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Old Jul 30, 2014 | 11:42 PM
  #1  
Brianbajnuth's Avatar
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From: Ny queens
Car: 87 GTA Trans Am
Engine: 5.7 350 TPI
Transmission: TCI transmission
Axle/Gears: 4th gen rear end. With 3.83
Rough idle when first start up

When I start my car in the morning or when ever for the first time after sitting all night it idles rough but as soon as it warms up it's perfect?!!? Wth is going on here?
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Old Jul 31, 2014 | 10:37 AM
  #2  
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From: Ny queens
Car: 87 GTA Trans Am
Engine: 5.7 350 TPI
Transmission: TCI transmission
Axle/Gears: 4th gen rear end. With 3.83
Re: Rough idle when first start up

Anyone? Help
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Old Jul 31, 2014 | 10:52 AM
  #3  
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From: Huntsville AL
Car: 88GTA
Engine: 5.7TPI
Transmission: Auto
Axle/Gears: 3.27
Re: Rough idle when first start up

I'll bite....Have you checked the following:

1. Any Codes?
2. Old or New Injectors?
3. Fuel Pressure readings?
4. TPS Setting?
5. IAC Setting?
6. Timing Setting?
7. Cold Start Injector still hooked up?
8. Cold Start Temp Switch working, (the one at front of intake that controls the Cold Start Injector)?

Is the engine stock, modified, crucified.......you know what I mean.

I could go on but I won't. There's just a lot of variables for "rough Idle"
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Old Jul 31, 2014 | 01:47 PM
  #4  
Brianbajnuth's Avatar
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From: Ny queens
Car: 87 GTA Trans Am
Engine: 5.7 350 TPI
Transmission: TCI transmission
Axle/Gears: 4th gen rear end. With 3.83
Re: Rough idle when first start up

No codes
Fuel injectors are new (I think)
Fuel pressure is 80 psi
TPS is good checked it
Didn't check timing and iac
I believe the car is running lean at idle too
And when I first start the car in the morning (it about 80 degrees here) it idles at 1000rpm and then it goes up to 1300 and runs perfect but isn't that to high?
When I drop the idle screw the car runs way to rough
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Old Jul 31, 2014 | 02:13 PM
  #5  
Brianbajnuth's Avatar
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From: Ny queens
Car: 87 GTA Trans Am
Engine: 5.7 350 TPI
Transmission: TCI transmission
Axle/Gears: 4th gen rear end. With 3.83
Re: Rough idle when first start up

Not stock motor
slp runners

Edelbrock heads ( crane rockers)

TCI transmission

Dynomax full exhaust
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Old Jul 31, 2014 | 03:24 PM
  #6  
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From: Huntsville AL
Car: 88GTA
Engine: 5.7TPI
Transmission: Auto
Axle/Gears: 3.27
Re: Rough idle when first start up

OOOOOOOOOOKKKKKKAAAAAAYYYYY Then........ Well, outta my league.
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Old Jul 31, 2014 | 06:09 PM
  #7  
Brianbajnuth's Avatar
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From: Ny queens
Car: 87 GTA Trans Am
Engine: 5.7 350 TPI
Transmission: TCI transmission
Axle/Gears: 4th gen rear end. With 3.83
Re: Rough idle when first start up

Anyone else??
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Old Aug 1, 2014 | 03:34 PM
  #8  
Brianbajnuth's Avatar
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Posts: 164
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From: Ny queens
Car: 87 GTA Trans Am
Engine: 5.7 350 TPI
Transmission: TCI transmission
Axle/Gears: 4th gen rear end. With 3.83
Re: Rough idle when first start up

The engine light comes on when first start up and then when warmed up and running fine **** off back.
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Old Aug 2, 2014 | 07:04 AM
  #9  
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From: Elm City, NC
Car: 87 IROC Z
Engine: 5.7
Transmission: 700R4
Axle/Gears: 3.27
Re: Rough idle when first start up

Are you sure the fuel pressure is 80? That's almost double what a TPI should be.
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Old Aug 2, 2014 | 01:29 PM
  #10  
Brianbajnuth's Avatar
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From: Ny queens
Car: 87 GTA Trans Am
Engine: 5.7 350 TPI
Transmission: TCI transmission
Axle/Gears: 4th gen rear end. With 3.83
Re: Rough idle when first start up

Originally Posted by hdis2002
Are you sure the fuel pressure is 80? That's almost double what a TPI should be.
Well unless my gauge is wrong I'm getting 80 and if I try to drop the pressure it starts to idle even rougher
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