Rough L98
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Intermediate
Joined: Jul 2001
Posts: 34
Likes: 0
From: Georgetown, KY , USA
Rough L98
I have a 88 that runs really good. The only problem I have is that if I sit in park and Rev the engine it Revs really rough around 13 or 14K RPM. I have also noticed this when driving (Vibration). I thought it may be the transmission (auto), but since it does this when in park I have to rule this out of the theory. What in the motor could be causing this vibration? Thanks in advance.
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Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
Re: Rough L98 (nobodyunknown)
The trans being in parked doesnt rule out the converter.
I had a vibration I couldnt track down..
I had to unbolt the converter from the flywheel and push it back away from it and then start the car and rev the engine.
That way I knew for sure if the converter was the culprit or not.
What you can also do is warm the engine to about 150 degrees and then shut it off and remove the serpentine belt off the engine.
Start the car and then rev it up to see if the vibration is still there...if its gone, then you have an accessory problem with the pulley system on one of them.
The balancer or damper is a major player for coming apart with age.
If you have the belt off, and have someone rev the engine while you listen and feel around the motor with a piece of wood and notice the vibes are strongest at the damper area,Id suggest to change it.
Wood helps transmit sounds and vibes which is why I suggested it.
Just be careful where you place it as to not set it on a spinning pulley or etc.
Other causes are bad motor mounts,exhaust leaks, etc.
Good Luck!
:)
I had a vibration I couldnt track down..
I had to unbolt the converter from the flywheel and push it back away from it and then start the car and rev the engine.
That way I knew for sure if the converter was the culprit or not.
What you can also do is warm the engine to about 150 degrees and then shut it off and remove the serpentine belt off the engine.
Start the car and then rev it up to see if the vibration is still there...if its gone, then you have an accessory problem with the pulley system on one of them.
The balancer or damper is a major player for coming apart with age.
If you have the belt off, and have someone rev the engine while you listen and feel around the motor with a piece of wood and notice the vibes are strongest at the damper area,Id suggest to change it.
Wood helps transmit sounds and vibes which is why I suggested it.
Just be careful where you place it as to not set it on a spinning pulley or etc.
Other causes are bad motor mounts,exhaust leaks, etc.
Good Luck!
:)
