leggo

Hi All
I have a new to me 2001 Accord Coupe LX, and I am having an issue with it.

When accelerating at a moderately steady speed, and I reach 55 mph - 65 mph, the car will shake from side to side. I don't feel any vibration in the steering wheel or front tires. I feel it more in the seats, I can see the dash vibrate, and I touch the passenger seat and feel it vibrate.

This vibration will quiet down at highway speeds of 70 - 75. I still can feel it slightly in my seat.

Interestingly enough, on hard acceleration from 2nd gear thru 5th, the side to side vibration is even more pronounced.

What I have done so far --- I needed new tires anyways --- put on new rims and Toyo tires, complete with 4 wheel alignment. Hoping this would take care of the vibration, NOPE. I brought it back to the garage, they did find one tire slightly out of balance and did another 4 wheel alignment. STILL NO GO.

Some other background -- I had the clutch slave cyl. replaced when I got it, but the clutch still presses very hard, mechanic said my pressure plate could be going.
Also - when braking hard I can feel the rear shaking ( it has drum brakes ) If I use the E- brake to brake, I can feel shaking even more pronounced. (But it is not the same side to side vibration)

Soooo... my question is where do I go from here and what could be some of the potential solutions to this side to side vibration.

Thanks for you help.
Leggo

98CoupeV6

I don't understand how a car can shake from "side to side" Is this different than a normal vibrating car?

leggo

Few more things --- the car is Manual trans., with 61,000 miles, 15" tires. All stock.

Also, what I mean by "side to side" vibration is that I can feel it more in the floor and the seat of the car --- also I can feel it in the dash. It really feels like the car is "shuddering" or vibrating side to side.

It is different from when you have a front tire out of balance and you can feel that in the steering wheel.

thanks
Leggo.

Big AL

Are you sure you don't have a tire that is out of round? Normal tire balancing machines won't detect out of round tires. When I bought my set of Toyo tires, I had them road force balanced the next day and they found one to be out of round. Only a road force balancer can detect this type of condition. It's a manufacturing defect and the place you bought it from should allow you to exchange it for a new one.

Big AL

Nevermind, I don't think that's going to help. You said you had this condition even before you got new tires.

98CoupeV6

Well since it happens when you're braking it's not the engine. I think you have a suspension problem. Either you or a mechanic need to thoroughly go over the ball joints and control arms. You might have a very loose ball joint or a twisted control arm in the front or rear. Did you run a carfax on this car before you bought it (why did you buy it if it was shaking?)?

fstop128

do u have any loud humming noise? wheel bearing maybe? when a wheel bearing went bad on my sister's old corolla the car vibrated pretty bad under the front floor board. it was the passenger front. took quite along time to go bad. she thought she had a rear brake issue also. it was all the wheel bearing.

leggo

98coupe - had a carfax - no issues. The mechanic (not my regular one) who checked it out said it was just the tires were old and out of balance, in regards to the vibration. We thought new tires/alignment would fix the problem. It did not.

The vibration that occurs when I brake just using the e-brake, is not the same vibration I get with accelerating. I included this information in hopes that it would add more clues.

Fstop - I don't have any hum at all -- I have had to replace two wheel bearings in other cars - and recognize the humming noise. Very distinctive.

Thanks

98CoupeV6

Okay...

I think the first problem is an engine issue. I think your engine is struggling to fire correctly. Check the air filter, clean the EGR ports, clean IACV screen. Change the spark plugs, test the resistance of the plug wires and check the condition of the cap/rotor. Even though you only have 61k I suspect your car was beaten to hell by a previous owner.

Second problem sounds like you need new rear rotors.

leggo

ouch - I hope it wasn't beaten to heLL. I am enjoying the ride otherwise.

You might be on to something - sometimes the car will fluctuate at idle - going from 600rpm-1300rpm - going back and forth. I dumped in some FI cleaner, and it seemed to help.

I have some shadetree experience working on cars - I can do some of this myself. Where do you suggest I start looking on the web to find out the step by step process to do some of the things you suggested. (or do I just do search on this forum)

Also - my car doesn't have rear disks -- just the drums. Will turning the drums(or new ones) resolve this. All my other cars had front/rear disks and changing the disks always fixed this type of vibration.