Hey guys, I don't really get into car forums much, so I figured i'd post in here and see if you could figure something out or gimme a starting point!

I'm having some "road noise" issues if you'd call them that. I'll give you the breakdown:

CAR:

1995 Honda Accord EX Sedan

PROBLEM:

Around 2500 RPM's, I can "feel" the engine beneath my seat(the drivers) and its sort of like a buzzing/vibrating noise or feeling. Its like the engine accelerates smooth, but then as as soon as it hits that spot(2500 RPM), it feels really rough, then gets back to smooth at like 2800 RPM maybe, around there. Its in accelerating/decreasing. I can't remember now, but I think if I"m in park and rev the engine I don't feel it... but I'll have to check that out and get back to you. But for now I think it only happens when im in gear.

POSSIBLE PROBLEMS(Things i've researched on the internet my own):

Timing belt is to tight

Heat shield bolts are beginning to come loose or it rattles

Those are about the two main ones I found. Anyone else have any other ideas??? I can't really take a engine noise video cause I dont have a camera right now. But hopefully i've described it well enough. I did get a new muffler on the car when I first got it, but I never drove it really to hear if that noise was present.

If you're feeling vibration it could be from a bad axle shaft or a bald spot on a tire.

A couple things to look at.

Tire pressure

Alignment

Spark- A bad spark plug or wire. (particularly looking for a plug that is arcing or a wire that is firing down the side of the plug which you will see from the ceramic being burnt.) Basically what happens is once the current gets high enough the spark jumps down the side of the plug and you are misfiring. It is normally noticeable at a low rpm (my car was at 2400 rpm for example) once the engine is spinning fast enough to have enough inertia to pull the non-firing cylinder around it will not be as noticeable.

Check your motor mounts, and as you mentioned the heat sheilding above your exhaust. If all else fails, check your brake rotors, if they aren't perfectly flat (most likely from being resurfaced or metal on metal scraping) they can actually cause vibrations.

Tires I think can be ruled out...I just got 4 new ones like say 2 weeks ago, balanced and everything, and there hasn't been any difference what so ever with this problem.

And by vibration though its not like a car vibrating, more of a humming/vibrating. But you can feel the vibration only underneath the accelerator pedal really. Its only noticeable to me though. I've asked passengers and they have never noticed the noise. maybe something that runs beneath the drivers side only??

also forgot to add though, about your spark comment. it doesnt happen at low-low RPM's though. Would that rule out this possibility? Like if i'm at 2100 RPM's, then I feel/hear no vibration at all. but as soon as it hits that 2500, I can feel it through the floor and then past that its gone. Its only like a 2400-2600 RPM range and that really is it which is why it seems so odd to me.

also forgot to add though, about your spark comment. it doesnt happen at low-low RPM's though. Would that rule out this possibility? Like if i'm at 2100 RPM's, then I feel/hear no vibration at all. but as soon as it hits that 2500, I can feel it through the floor and then past that its gone. Its only like a 2400-2600 RPM range and that really is it which is why it seems so odd to me.

actually because it was at specific rpm's is what made me think a spark issue.

I also know it had a new timing belt on there about 20k miles ago and it was done by a shop. So maybe that would rule out that possiblity? or at least move it down the list of things I had seen on other forums.

Looks like things to check are:

Heat Shield

and the Spark Plug you had talked about

are there any other symptoms of the spark plug problem i should check for?

does your exhaust run down that side? it could be loose somewhere and the amount/speed of air flowing through at that specific rpm gets it to juggle.

also, does it do it at all gears at that rpm? if it does then it's probably something powertrain-related. if it only does it at highway speed, like 5th gear or something, then it may be speed-related and may be chassis/suspension/etc.

could be something wrong with your tranny sinec it only happens when in drive...could also be something as stupid as a dirty sensor. its nearly impossible to diagnose without looking at the car in person...

It's a definite exhaust or mount problem. I'd put money on it. Check all the joints and mounts. Could also be the heat shield, but that's more of an obvious tin-on-tin sound. IIRC, that has a flexible joint on it as well. This could have a hole in it, or a break.

i had this problem on my stratus...my exhaust was loose....it rattled at 2000-2400...then it was fine

but the motor mount one sounds like a good possibility too

I'd definitely check the mounts and exhaust first. Changing spark plugs is usually worth the effort either way (not expensive so do it for good measure).

depending on the vibration it could be a stretched timing belt as well as an overly tight one. I've had a specific RPM vibration from a loose belt, too tight usually makes more of a sound than a vibration in my experience.

Could be transmission if it does it under a certain load but i'd probably rule this one out based on what you've said so far. But that doesnt mean you can't have the tranny oil/filter changed for good measure too

oops after rereading your first post i wouldn't rule out tranny so quickly. crawl under the car and check the condition of the boots on your cv joints.

hey guys, was browsing through the forums and found this and forgot I had started this post lol.

I'll keep you updated and maybe you can rule things out!

This so far are:

Took it in to the honda dealership and they test drove it and said it may be a heat shield problem. So they removed that and in the process of that realized that when I got a new muffler installed at another place that instead of a new stock exhaust it was an aftermarket one. So I think my next stop is to take it in there and have em look it over.

Timing belt was rechecked and they said it looked perfect.