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C4 ZR-1 Discussion General ZR-1 Corvette Discussion, LT5 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track

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Old 05-05-2005, 11:13 AM   #1
ShawnZR-1
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Default Low RPM stumble/miss

Help me out here, it seems my beast has developed an attitude at low RPM's.
It seems to happen under the following conditions:
Key on or off,
Temps normal
RPM less than 1500RPM
Throttle position >25%
No Codes set.

As soon as it gets over 2K, it pulls to the stratosphere, all the way to 7000+.

I was trying to think if it did it at all before I installed the headers, but I can't say for sure. I don't think it did, but I can't swear to it.
Is false knock a possibility? I haven't scanned it yet but it seems that even last year when I had the stock manifolds on it, I had some knock counts. I run 93 all of the time.

Ok, hit me up with the ideas!
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Old 05-05-2005, 01:42 PM   #2
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Check plugs for fouling
Check plug wires to make sure they are seated
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Old 05-05-2005, 03:14 PM   #3
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Quote:
Originally Posted by Jeffvette
Check plugs for fouling
Check plug wires to make sure they are seated
I checked the wires last night, I'll check the plugs this weekend when the car has a chance to cool enough. FWIW, the plugs and wires were the first things I thought of.
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Old 05-05-2005, 03:28 PM   #4
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Quote:
Originally Posted by ShawnZR-1
I checked the wires last night, I'll check the plugs this weekend when the car has a chance to cool enough. FWIW, the plugs and wires were the first things I thought of.

Did you use an ohm meter to check the wires? I had one that was inconsistent, the motor still ran reasonably fine, and the wire itself looked perfect, but the connection was frayed at some point - if the wires are original, time to replace them.
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Old 05-05-2005, 04:19 PM   #5
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I replaced the wires around October last year, they're not the originals. I only checked to make sure they were seated. I didn't go under the plenum to check them end to end yet. I have a feeling it's a mucked up plug, but I haven't had a chance to pull them. The car doesn't cool down enough at night and in the morning, well, I do have to go to work. I'll yank them out this weekend and see.
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Old 05-09-2005, 11:30 AM   #6
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Update: #2 plug was fouled as all get out. Black and carboned up. Runs like a purring kitten now! God, I love simple fixes!
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Old 05-09-2005, 02:42 PM   #7
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Glad to see you found a simple fix
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Old 05-09-2005, 05:15 PM   #8
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Originally Posted by ShawnZR-1
Update: #2 plug was fouled as all get out. Black and carboned up. Runs like a purring kitten now! God, I love simple fixes!
Good job, but...what caused the fouling? Bad injector?
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Old 05-09-2005, 05:23 PM   #9
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Good job, but...what caused the fouling? Bad injector?

BAD ATTITUDE!!!
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Old 05-09-2005, 05:23 PM
 
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