Misfire = Vibrations?, but no codes?
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TECH Addict
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Joined: Feb 2006
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From: Germantown Hills IL
i did pull my plugs, no luck there,, they all looked great and are about a year old,, new wires too,,, did check the pushrods,, had one that had a curve to it, so i replaced them all,,, no luck there either,,, it almost does sound like it has a "miss" to it, but not sure and no means of checking,,, i do get a p0327 code which is a knock sensor,, i dunno,, im at a lose as u can tell by how old this thread is.
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Joined: Aug 2005
Posts: 2,305
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From: Monroe,NY
We put a 383 sbc 4 speed in a 77 camaro and my friend bought a brand new center force clutch with the centrifugal weights on the pressure plate. The 383 was in my truck before his camaro and never had a vibration. With his old motor he had no vibration.But when we drove his car at 2200 rpms till 4000 rpms he had a horrible vibration through the shifter. He had the driveshaft balanced,we checked the rear and ran motor without tranny and still had vibration. Took off clutch and pressure plate vibration was gone. Ripped weights off pressure plate and now his car is vibration free.
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Joined: Mar 2009
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I know this post has some age to it but the same bad penny is in my garage!
New L76 w/DOD junk removed and 6 speed, I have a slight vibe between 1700-2600 rpm, in neutral or going down the road. Shows random misfires with #5 and #8 getting considerably more. I swapped coil packs around, injectors swapped, 2 new sets of plugs, new wires, all wiring traced and checked, compression tests at 170 across all cyl., pulled valve covers, everything normal there, no vac. leaks or exhaust leaks.
I pulled the flywheel/clutch (all new stuff) and put it back together with a stock flexplate and get the same vibe in the same rpm range. Changed balanacer to a new ATI balancer, same results.
As far as the misfires go, you cant really feel them but when the motor smooths out above 2600 rpm, there are a lot more misfires showing.
This is driving me NUTS..........
New L76 w/DOD junk removed and 6 speed, I have a slight vibe between 1700-2600 rpm, in neutral or going down the road. Shows random misfires with #5 and #8 getting considerably more. I swapped coil packs around, injectors swapped, 2 new sets of plugs, new wires, all wiring traced and checked, compression tests at 170 across all cyl., pulled valve covers, everything normal there, no vac. leaks or exhaust leaks.
I pulled the flywheel/clutch (all new stuff) and put it back together with a stock flexplate and get the same vibe in the same rpm range. Changed balanacer to a new ATI balancer, same results.
As far as the misfires go, you cant really feel them but when the motor smooths out above 2600 rpm, there are a lot more misfires showing.
This is driving me NUTS..........
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TECH Resident
Joined: Apr 2010
Posts: 926
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From: Central Texas
I had a bad SLP under-drive pulley on mine that would cause the knock sensors to pull timing and cause a misfire and not set any codes. Chased it for 8-9 years and spent mega bucks chasing my tail. I finally set down and made a list of all the mods-issues When I came to the SLP Cold air and SLp underdrive pulley I got for Christmas in 2001 ( this was 2010) I spent 55 bucks for a new stock pulley and belt and the car ran like a BatOuta Hell!! no missing at all.....FWIW
