C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Another stumble stutter thread. need advice please!

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Old Jul 9, 2010 | 04:28 PM
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Default Another stumble stutter thread. need advice please!

I think I've read all the threads pertaining to my issue. Lots of great info here!
I purchased my first Corvette last fall, '94 6spd w/49K. It needed a little TLC.
it runs fine untill it warms up, the hotter the temp gets the worse the miss. Below 2k and at WOT (or heavy throttle) it runs fine. the stutter is prominate between 2-3k under light throttle. once it reaches 3k it picks back up like nothing is wrong.
I'm trying to fix this issue myself. last resort changing the Opti, which I'll pay to have done.
Here's what I've done so far.
Plugs/wires
ICM
Coil
confirmed injectors, all at 12ohm.
20mph WOT in 5th gear. no stutter.

Any ideas?

thanks in advance for your input.
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Old Jul 9, 2010 | 04:52 PM
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Originally Posted by sledge
I think I've read all the threads pertaining to my issue. Lots of great info here!
I purchased my first Corvette last fall, '94 6spd w/49K. It needed a little TLC.
it runs fine untill it warms up, the hotter the temp gets the worse the miss. Below 2k and at WOT (or heavy throttle) it runs fine. the stutter is prominate between 2-3k under light throttle. once it reaches 3k it picks back up like nothing is wrong.
I'm trying to fix this issue myself. last resort changing the Opti, which I'll pay to have done.
Here's what I've done so far.
Plugs/wires
ICM
Coil
confirmed injectors, all at 12ohm.
20mph WOT in 5th gear. no stutter.

Any ideas?

thanks in advance for your input.
Suggest you don't change the Opti without a pretty solid diagnosis, especially if you hire it out- the bill will be sobering.
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Old Jul 9, 2010 | 05:53 PM
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i think if you can change wires and plugs, you can change the opti too.
I am having the same problem, but in a camaro LT1. I just did the opti because i found the cap had a crack, while there i also did the plug wires and did the plugs about 1k miles back. No difference.
I would also check the fp, and if you can get a datalogger on the car.
matt
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Old Jul 9, 2010 | 07:34 PM
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My next move is to take it to the local stealership to run a diagnostic check.
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Old Jul 10, 2010 | 02:54 PM
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Originally Posted by sledge
My next move is to take it to the local stealership to run a diagnostic check.
You said it all with "stealership". There might not be anyone in the shop who has ever been under the hood of a C4. I would look for a Corvette tuner if I got stumped. The dealer will throw parts at the problem, and if they installed a part, you "needed" it.
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Old Jul 10, 2010 | 03:30 PM
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Try this, and report back what you find...

http://www.corvettebuyers.com/c4vettes/codes.htm
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Old Jul 10, 2010 | 03:47 PM
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my injector ohms were 16.2, not saying yours are bad, just noting the difference.
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Old Jul 10, 2010 | 05:13 PM
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You might just look at your gas cap. try your normal up to 2000 RPM's with the cap loose.

Last edited by coupeguy2001; Jul 10, 2010 at 05:19 PM.
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Old Jul 11, 2010 | 08:48 AM
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any fouled plugs?
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Old Jul 11, 2010 | 11:58 AM
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Checking the ohms on the injectors doesn't make them right. Mine were all perfect, but they were horribly clogged, causing it to run very rough at certain parts of the power band (shuddering probably from fuel deprivation), and it idled horribly. I bought a set of rebuilt injectors, and it ran perfect.

Checking the ohms on the injectors doesn't make them right. Mine were all perfect, but they were horribly clogged, causing it to run very rough at certain parts of the power band (shuddering probably from fuel deprivation), and it idled horribly. I bought a set of rebuilt injectors, and it ran perfect.

It's easy to check. Find my thread, "94 has a miss.... opinions?" and you'll see all that we did to fix it.
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Old Jul 11, 2010 | 12:06 PM
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Originally Posted by Bob2.0
Checking the ohms on the injectors doesn't make them right. Mine were all perfect, but they were horribly clogged, causing it to run very rough at certain parts of the power band (shuddering probably from fuel deprivation), and it idled horribly. I bought a set of rebuilt injectors, and it ran perfect.

Checking the ohms on the injectors doesn't make them right. Mine were all perfect, but they were horribly clogged, causing it to run very rough at certain parts of the power band (shuddering probably from fuel deprivation), and it idled horribly. I bought a set of rebuilt injectors, and it ran perfect.

It's easy to check. Find my thread, "94 has a miss.... opinions?" and you'll see all that we did to fix it.
thanks. I read your thread yesterday and gave it a try. Each injector unpluged made it run worse. I was hoping to find this was my issue.
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Old Jul 11, 2010 | 12:16 PM
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Now I'm getting some where. I just don't know "where" is? lol

I got three codes:
H41 Ignition control circuit.
H18 ???
H72 VSS signal circuit error
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Old Jul 11, 2010 | 01:11 PM
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anyone know the location of the VSS. I squeezed under there but I don't see it?
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Old Jul 11, 2010 | 05:02 PM
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Originally Posted by sledge
anyone know the location of the VSS. I squeezed under there but I don't see it?
VSS is on the driver's side of the trans extension housing, just aft of an inspection plate with 6 bolts. There is an electrical connector on it.
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