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Can't give it more than 25% throttle

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Old Dec 30, 2014 | 08:09 PM
  #1  
cbrcrx's Avatar
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From: Nashville
Car: 1992 Camaro RS
Engine: 305 TBI
Transmission: Manual
Axle/Gears: ?
Can't give it more than 25% throttle

Hello, I have a 92 Camaro RS 305 TBI manual transmission with 44k miles. This morning I started it and tried to drive to work and every time I try to gas it, it would cut out and sputter. The RPMs didn't matter, only how much gas I gave it. Then when I went home at lunch, 4 hours later, it ran perfectly. Any ideas?
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Old Dec 30, 2014 | 08:44 PM
  #2  
ex-x-fire's Avatar
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Re: Can't give it more than 25% throttle

Could be low fuel pressure.
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Old Dec 31, 2014 | 07:53 AM
  #3  
cbrcrx's Avatar
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From: Nashville
Car: 1992 Camaro RS
Engine: 305 TBI
Transmission: Manual
Axle/Gears: ?
Re: Can't give it more than 25% throttle

Do you think if it was the fuel pump that it would do that one time and not the next or does it just get progressively worse?
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Old Jan 1, 2015 | 07:00 PM
  #4  
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From: Alpine
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Can't give it more than 25% throttle

Originally Posted by cbrcrx
Do you think if it was the fuel pump that it would do that one time and not the next or does it just get progressively worse?
It can act differently depending on what is failing in the pump. Renting a fuel pressure gauge is cheap and should be your first step in diagnosing it. You'll have a bad day if you just replace the pump and its still having an issue.
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Old Jan 2, 2015 | 11:32 PM
  #5  
92RS shearn's Avatar
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From: Wichita, KS
Car: 92' RS
Engine: LO3
Transmission: Probuilt 700R4
Axle/Gears: 3.70 9-bolt
Re: Can't give it more than 25% throttle

Somewhat similar to me in my thread:
https://www.thirdgen.org/forums/tech...orly-over.html

My main symptom was a bad ICM, still determining what is causing the ICMs to go bad.

As others mentioned it is still best to check fuel pressure.
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Old Jan 3, 2015 | 12:40 PM
  #6  
cbrcrx's Avatar
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From: Nashville
Car: 1992 Camaro RS
Engine: 305 TBI
Transmission: Manual
Axle/Gears: ?
Re: Can't give it more than 25% throttle

I just figured out it is way worse the warmer it gets. Today I barely made it home. It sputters and backfires the whole time I try to give it gas. Sometimes it runs smoothly but only feels like four cylinders. I am ordering the attachment for the fuel pressure gauge so I can check the pressure.
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Old Jan 10, 2015 | 03:21 PM
  #7  
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From: Nashville
Car: 1992 Camaro RS
Engine: 305 TBI
Transmission: Manual
Axle/Gears: ?
Re: Can't give it more than 25% throttle

Well, I checked the fuel pressure and it was around 12 psi. A couple of friends that rode with me thought it felt more like an ignition problem. So, I changed the plugs (gapped properly), plug wires, distributor cap/rotor and coil with all quality brands. It still spits and backfires, though not as bad. Today I could drive around normally. But, if I gave it too much gas it would still do it. It was only 25 degrees today. It may get worse when it warms up.
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Old Jan 10, 2015 | 04:18 PM
  #8  
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Re: Can't give it more than 25% throttle

Does any of your friends have an ign.coil you could try out?
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Old Jan 10, 2015 | 04:21 PM
  #9  
cbrcrx's Avatar
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From: Nashville
Car: 1992 Camaro RS
Engine: 305 TBI
Transmission: Manual
Axle/Gears: ?
Re: Can't give it more than 25% throttle

I just put the new coil in.
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Old Jan 10, 2015 | 04:35 PM
  #10  
92RS shearn's Avatar
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From: Wichita, KS
Car: 92' RS
Engine: LO3
Transmission: Probuilt 700R4
Axle/Gears: 3.70 9-bolt
Re: Can't give it more than 25% throttle

Did you have the ignition control module checked? They can check it at most auto stores.
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Old Jan 10, 2015 | 04:37 PM
  #11  
cbrcrx's Avatar
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From: Nashville
Car: 1992 Camaro RS
Engine: 305 TBI
Transmission: Manual
Axle/Gears: ?
Re: Can't give it more than 25% throttle

I just ordered a new one. I figured since it wasn't too expensive and mine was 23 years old, I would just replace it.
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Old Jan 17, 2015 | 01:11 PM
  #12  
cbrcrx's Avatar
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From: Nashville
Car: 1992 Camaro RS
Engine: 305 TBI
Transmission: Manual
Axle/Gears: ?
Re: Can't give it more than 25% throttle

You guys were right about the cheap aftermarket ICM. It ran about a mile and quit. Now it starts and quits immediately. I just ordered an AC Delco one.
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Old Jan 25, 2015 | 09:03 PM
  #13  
cbrcrx's Avatar
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From: Nashville
Car: 1992 Camaro RS
Engine: 305 TBI
Transmission: Manual
Axle/Gears: ?
Re: Can't give it more than 25% throttle

Well, I found out both head gaskets were leaking and the valve seals need replacing too. I guess that's what happens to a car with only 44k miles in 23 years?
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