rough idle?

[Bad-Day]

I have a 2011 RSS, and I have only owned it for a couple months. It seems like it isn't idling as smooth as it did when I purchased it. Starts easy, but once it warms up it fluctuates around 1500 RPMs (give or take 100 RPMs, you can see the tachometer needle moving and hear the engine loping. It has 15k miles, does this sound normal??

Thanks in advance, Luke

[pegasus1300]

check the little vacuum lines on the left side of the throttle body.With age they crack and leak causing a rough idle,mileage is irrelevant. Go to NAPA and get some silicone hose and replace them,an easy job. Also cheap. The new lines must be cut to the same length as you are replacing. Good luck,just go do it........you know you want to.

[GOZFST]

Also try some good fuel injector cleaner like Sea Foam.

[Bad-Day]

I appreciate the replys. So with the way I am describing it, does it seem to be idling a bit rough???

[JerryB]

Hi Bad-Day,

Re: does this sound normal??

My '08 idles from 1350 to 1450 normally. Your 100 RPM fluctuation seems normal to me.

Jerry Baumchen

PS) A change of those air hoses is always a good thing.

[Chupaca]

It is on the high side and the suggestion to change the hoses to silicone on the vaccum to throttle body is a good thing to do regardles. I have a 2012 RS and they started going after about 2 years some faster than others...

[Bad-Day]

Will do on the hoses, does anyone know the diameter and the length I will need, I will stop at the parts store on the way home..

[pegasus1300]

NAPA will sell you the hose in a bulk container about 4 or five feet You will measure each hose and cut your new hose to that length. I think mine cost me about $5.00. I don't remember the diameter of the hose,someone else will have to chime in on that.

[Bad-Day]

I changed out the vacuum lines, replaced the spark plugs and air filter, even put in some gas additive. We will see tomorrow how it runs. I appreciate all the help. The entire air box had oil on it, even some had dropped onto the engine, is this normal?

[BLUEKNIGHT911]

I changed out the vacuum lines, replaced the spark plugs and air filter, even put in some gas additive. We will see tomorrow how it runs. I appreciate all the help. The entire air box had oil on it, even some had dropped onto the engine, is this normal?

NOPE it isn't, there are how to threads on what you can do to fix it tho .... it involves dis-connecting ( on left side ) the hose that connects to the Air Box ..... and putting any small fuel filter on the hose and add a hose and direct down to the ground ..... You must put some course foam into the hole that you took the hose off of ..... end of problem ..... Mike

[Bfromla]

Also try some good fuel injector cleaner like Sea Foam.

But have found Barryman B-12 system cleaner to work better & cheaper personally

[Bad-Day]

What do I search for, I need to get this fixed with that modification? Thanks

NOPE it isn't, there are how to threads on what you can do to fix it tho .... it involves dis-connecting ( on left side ) the hose that connects to the Air Box ..... and putting any small fuel filter on the hose and add a hose and direct down to the ground ..... You must put some course foam into the hole that you took the hose off of ..... end of problem ..... Mike

[SpyderAnn01]

Will do on the hoses, does anyone know the diameter and the length I will need, I will stop at the parts store on the way home..

The Napa part number is H466. I see that you already replaced the lines but I'll leave this here with the part info for the next guy.

[Matahead]

Will do on the hoses, does anyone know the diameter and the length I will need, I will stop at the parts store on the way home..

Using the NAPA site found the hose is: 6 ft long.

Silicone Vacuum Hose I.D.

.1093 in.

I will put this on my To Do List.