Rough Idle - Honda Prelude Forum

mlevinson · 06-09-2008, 09:24 PM

Hey guys I have a 92 Prelude 2.3 Automatic for about a month. It had a rough idle when I bought it.
Thinking it just needed a tune up. I put Plugs wires cap and button on it. Still the same problem.
An example would be first thing in the morning,m I start it up and it idles fine in park at about 1000 RPMs.
I put it in gear and it will idle fine at about 750 RPMs. When I say fine, I mean you can barely tell the car
is running its so smooth. I drive it to the store I usually stop at and the idle may drop to 500 rpms in gear and idle
rough as you know what. In park it idles at 750 and idles rough also. The next stop light I stop at it will be back at
750 in drive and idle rough again. When i put it in gear it will be back at a 1000 and be smoother but not as much
as it was earlier. It seems almost completely random. The only thing constant is its randomness. It doesnt always
start out smooth. It could be idleing rough as you know what first thing in the morning and get better at some point and
get worse at another. It idles so rough that the steering wheel shakes the cange in my cup holder, well every thing shakes.
Sometimes at lights When its really bad I will hold the brake and give it a little gas and it will gets better. I tried idleing it
up some and it seems to help only marginly. Any help on ideas that would help me to make it run smooth all tha time would
be a great help. Generally I would like to go cheap parts first unless you really think you might know what the problem is.
I also replaced the timing belt since I bought it ( not because it was broke...I just wanted to know that it was new). That
made no change. Thanks Randy

JoeRogue · 06-10-2008, 05:16 AM

So from what I gather you are having this problem when it warms up?

mlevinson · 06-10-2008, 08:17 AM

It will happen any and all the time. It could be fine one moment then idle rough the next. The idle speed also changes at random. It never gets over
1000 rpm. It may idle good all the way to work or it may change 3 times on the way to work.

rayslude · 06-10-2008, 10:27 AM

read my signature.

Search for erratic idle, bouncing idle, surging idle...you'll get more than enough info there. Sound like you may have air in your water lines. Also search for IACV.

thegamettt · 06-10-2008, 11:00 AM

I had the say problem, Its most likely the IACV, if the tune didn't do anything. It just idles low as sh!t huh. ^ Hes got you in the right direction.

mlevinson · 06-10-2008, 03:46 PM

I seen all the articles and post from the surging from having a air pocket. I dont think thats it because after I put on the timing belt I had that preoblem and it was very obvious. I will look more into the IACV. Any other ideas will be greatly appreciated.