Loud Vibration When Letting Off Gas. Help!

DamShavers

New Member
Hello everyone. I am new here and usually don't post on many forums, but this problem has me pretty worried and I cannot figure out what it is. I drive a 99 Integra LS, automatic transmission, 1.8 liter 4 cylinder engine.

The problem I am having is when I am driving greater than 30 mph and I let off the gas pedal. When I do this, there is a very large rumble/vibration that comes from the front end. I can feel the vibration in my feet as well. To stop it, I either need to slow to below 30 or accelerate again. I don't notice any RPM fluctuations and it does not effect speed when this takes place. Generally, in the morning it does not do this, but it happens in the afternoon when it is warmer and I drive longer distances. I did a visual under the hood and I could not find anything loose. It has been doing this for about a week and today, it started to vibrate loudly when I turned on the heater.

Thanks for taking the time to read this and your ideas. If you need anything more specific, please let me know. Thanks!

-Dave
 

phatintegra

Banned
Sounds like a heat shield if your running stock header/cat if so could be either one but I would check the cat first.
 

DamShavers

New Member
Sounds like a heat shield if your running stock header/cat if so could be either one but I would check the cat first.
Mounts and axels seem to be good. I am an aircraft mechanic in the AF but don't know squat about vehicles. What am I looking for when I look at the cat? It is stock. Dents/rusting? Thanks!

-Dave
 


teggygrl08

BBHG.. one love.
check your lug nuts. seriously, make sure theyre tight. same thing happened to me when i let off the gas and my wheel almost fell off on the highway. i kept hearing a vibrating noise for like a week and then that happened.
 

jznsn2u

Active Member
check your lug nuts. seriously, make sure theyre tight. same thing happened to me when i let off the gas and my wheel almost fell off on the highway. i kept hearing a vibrating noise for like a week and then that happened.
But don't snug them on too tight :naughty:. I would crawl under the car and check if the axle boots are ripped as well.
 

jznsn2u

Active Member
OOhhhhh shoot I just noticed, OP is in the AF :thumbs up. Woooot! What air frames do you work on?
 

DamShavers

New Member
OOhhhhh shoot I just noticed, OP is in the AF :thumbs up. Woooot! What air frames do you work on?
I am a crew chief on B-52s here at Barksdale. Been working Buffs for nine years now. Good times. What about you jznsn2u?

Looks like I have a good amount of things to check out. I will re-look at the engine mounts. I looked at them, but didn't think that was the cause. My wife drives a Pacifica and she had bad engine mounts which caused a knock when accelerating. It certainly seems like it is coming from under the hood somewhere though. The loud rumble with vibration takes place about 2 seconds after I let off the gas above 30 mph. Its not immediate. Like I said, I don't know much about cars but I am armed with a trusty Haynes manual and a day off. Thank you for all the suggestions. I will check it and repost. Take care!

-Dave
 

skateboardb

New Member
My car makes the same noise. I have motor mounts, a skunk 2 intake manifold, and a after market fly wheel. Can the noise be because of any those parts.
 

Cripton805

New Member
Could need a tune up?
Could be lagg due to misfire? or bad sparks, Dizzy cap, etc... too.

Just putting it out there

Strange about the heater though.
Does it overheat?
 
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