I have this strange engine vibration that started about 2 months ago and it's annoying the crap out of me. Every time I come to a stop and RPMs go back to idle the car steadily vibrates, I can feel it real good in the steering wheel and the interior makes all kinds of noises because of this. It seems to almost (still there a bit) go away when the car is in neutral/park.

Well, having read a lot of posts about changing the IACV I thought that might be my problem. So today I went ahead and changed it. Cleaned the throttle body while in the process. Had to reset the computer by disconnecting the battery because it was idling funny when I put everthing back together. But anyway... although I think the idle has improved the car still vibrates (engine that is). There is no engine light and no codes to indicate what the problem could be so I'm confused but need to resolve this.

I am taking suggestions. Any Honda mechanics here?

 

I have the same problem after installing my subwoofer. Do you have a subwoofer or aftermarket audio system in your car?

 

could be your valves.. iacv is supposed to tick actually

 

I think your engine mounts are toast since you said it goes away when it's in N & park. That take's the engine load off.

 

I do, but it's been there for 2+ years and I don't see how that could contribute to the problem at all.

 

Front and right side were changed about a year ago. And actually at the time my front mount was busted quite badly before it was changed, however I had no problems with engine vibrating.

 

could it be just the rear mount since I changed the other 2 already?

 

What are you seeing RPM wise when this all happens? Is the vibration due to idle dropping too low?

 

No, idle does not drop too low, it looks normal especially with the new IAC valve. However when it's in Drive and I stop at a light it still drops to idle speed and vibrates. It used to be "silky smooth" before, at times I didn't even know the car was running...

 

Trans mounts maybe as well.

 

My guess is engine mounts. You can check your tranny mounts underneath you car sitting right below your tranny.

How did you go about resetting the ECU? I had this EXACT same problem. Removing the negative wire from the battery for a little over 15min and then putting it back on and running the car at idle for a little over 20min solved this issue. I'de reset the ECU again....it won't hurt and may fix it...just do it for as long as I did b/c I know that worked for me

 

When's the last time you changed the plugs and ran some fuel injector cleaner through the system? (Techron?)

 

Also, you may want to check for any vacume leaks/hoses disconnected.

 

how do u do that on the mounts ??

 

maybe a year and a half ago I put some Denso Irridium plugs in (as far as I know they're meant to last aprox. 100k), and I used some Lucas injector cleaner recently actually after the problem started which did not really help. I heard techron is good but we don't have that available here in Canada.

looking from the top of the engine the vacuum line going to the front mount seems to be connected. When I was changing the IACV I checked and re-checked everything in that area and everything seemed fine in terms of hoses. Only thing I noticed when I removed the icebox intake tube going to the throttle body is that there was a short ground cable underneath there that completely broke off. I didn't consider it a big deal because I have an extra 0 gauge piece of cable running from the battery to the engine block. However maybe it's there for a reason.

Which hoses to check exactly?

The vibration seems to be very noticeable only when in gear and idling with the engine warmed up. I never changed my tranny mounts. I got the car at 120Kms and so far did not experience any issues with the tranny in the last 100Kms. Shifts fine, no problems.

 

There are also some vacume lines that come off of the rear plenum. Just make sure all are connected and you don't have any cracked lines.

 

As mentioned, tranny mounts or rear engine mount.

Also, get under the car and make sure the hydraulic lines are connected to the engine mounts (front and rear have them). I had a similar issue and it turned out one of the lines was not connected.