Rough Idle

brewerp93 · July 31, 2015, 05:43:54 PM

My SHO now has around 65000 miles on it and I feel like it is having somewhat of a sputter in idle, once the rpms rise the problem seems to go away I took it in and had them look at it at the dealership and they told me that it ran great and it was just turbo lag, but to me it doesn't feel like lag. I am no expert on turbos, but it feels more like a slight hesitation than a lag to me. I'm thinking that my next step is going to be pulling the plugs to see what those are looking like other than that I am unsure of what the issue could be unless it is just timing in the computer or truly is just lag.

smeans92 · July 31, 2015, 06:00:56 PM

I would pull the plugs and check them. When is the last time they were changed? I had a cold idle problem with mine, I changed the plugs with Motorcraft sp534 gapped at .030 and it cleared up the problem. The old plugs were pretty bad, gaps were ranging from about .034 to .040 and the electrode was almost gone. The new plugs are about $24 for six at Oreilly's.

brewerp93 · July 31, 2015, 06:12:24 PM

I bought the car with 45,000 on the odometer and it was a ford certified vehicle, so I am not sure if they changed it in the certification process or if that is something that they don't mess with but I have never personally changed them. I am also under warranty and am curious if that would be covered I might save a few bucks that way.

SHOdded · July 31, 2015, 06:52:34 PM

First thing: always pull codes. Pulling the plugs is always a good idea though. Unless you have a maintenance contract, plug change is not covered, and even if it were, wouldn't be till 100,000 miles, since that is when they are technically due.

brewerp93 · July 31, 2015, 07:01:59 PM

Yeah one of my buddies was just telling me the same thing ill just end up pulling them to see how bad they are looking, and when I took it in initially for the issue they did plug it in and there were no codes that came up for anything I think thats why they just told me everything was fine.

BiGMaC · July 31, 2015, 07:07:52 PM

Agree with Manu entirely. Reading any codes comes first. I recommend doing it yourself. There are DTCs relative to misfires, etc, that don't light a CEL until certain criteria are met. Also it will give you something to check against after you clean/regap or replace the plugs. Likes smeans92, I found about the same range of gaps from the factory. It only takes about 30 minutes after the first time to check the plugs. I do it every 10K. Also pay attention to whether it does it after the O2 sensors are warm and your running closed loop.

brewerp93 · July 31, 2015, 07:13:06 PM

Ok well I will definitely be pulling them then that is the most basic solution to the issue. I have also read that the plugs in mine (if they have not been readjusted since they were new) would have the improper gap. I read somewhere that ford went back and shortened the recommended gap on the plugs

SHOdded · July 31, 2015, 07:14:09 PM

BTW, the advantage of the smallish twin turbos is the virtual elimination of lag. So if you feel there IS a lag, there's an issue with the powertrain somewhere, and it is NOT normal.

Is your SHO still stock? The gap for stock is supposed to be a bit wider at around 0.035, compared to around 0.030 if you are running a tune.

brewerp93 · July 31, 2015, 07:48:36 PM

I am really looking for the source that initially found it but I am almost certain that I had seen somewhere that the original gap that came on the 2010 and 11 was over .040 and then they realized that it needed to be smaller. Fingers crossed but I am hoping that I just pull the plugs and that is the issue but yes it is still stock I don't want to void the warranty just yet because I did buy it used so if there is something in the powertran than it is covered up to 125000 for me.

AJP turbo · July 31, 2015, 08:03:00 PM

No such turbo lag exists in these cars...I've seen light duty tractors and motorcycles with larger turbos

smeans92 · July 31, 2015, 08:40:34 PM

Check all the clamps on your charge pipes as well, a small boost leak can make the car feel like it lags. I had a couple lose clamps when I first got my SHO, I've heard that it is pretty common on these vehicles.

brewerp93 · July 31, 2015, 09:13:45 PM

Is there an effective way of seeing if my system is leaking anywhere without having to check everywhere a hose is attached or by doing the soapy water trick?

BiGMaC · July 31, 2015, 09:49:55 PM

Quote from: brewerp93 on July 31, 2015, 09:13:45 PM
Is there an effective way of seeing if my system is leaking anywhere without having to check everywhere a hose is attached or by doing the soapy water trick?

Sorry... Not that I know of... After watching others chase boost leaks I went to hard Hotpipes to replace the plastic oem. Those plastic pipes can crack anywhere, not just connectors. If you aren't seeing overboost conditions on your reader I would think plugs and electrical first.

SHOdded · July 31, 2015, 09:51:09 PM

Given that the PCV system is the way it is, if you spot a slurry of oil/grime on the hoses, that would be a tell-tale sign of a possible leak.

ZSHO · July 31, 2015, 10:35:11 PM

I would forget about the soap and water,just go to your local parts store and purchase a can of carb cleaner and spray a section at a time with the engine running and listen for any idle fluctuation and proceed from there. Z