Hi, I just started having a problem with the idle surging on my 2014 3.7L V6. This problem suddenly appeared and I am at a loss as to what is causing it. I have added a BBK CAI and changed the Headers and the exhaust system. But, the surging idle problem didn't occur after I replaced these items. It also started after I filled up, I am in Europe and I use the European version of 87 Octane Gas. (95 RON). This fuel also has 10% ethynol in it (E10). I have been using this fuel since I first purchased the Mustang, and it has never been a problem. Is there something else that can cause a surging idle. I am currently running without CATS. I am going to put new pipes on next week with the CATS installed, since the CEL never goes off now. Any advice would be greatly appreciated, I am at a loss with this problem.

 

Most likely it is a vacuum leak. It is trying to correct the air to fuel ratio.

 

Thanks for the advice, I will check the vacuum lines and see if anything is loose.

 

Only happens during Idle, runs fine otherwise.

 

I looked for Vacuum Leaks and can't find any, I did see some interesting info on the Mass Airflow Sensor on You Tube. It is doing exactly what the individual on You Tube stated in his Video. I am going to get some CRC cleaner and try that and see what happens. I'll let you know if there is any change in the Idle.

 

Did you diconnect the battery during the install to reset the values? ... Or maybe the relearn process was incomplete?!

 

Big huge negative my good sir. OP, I can almost with certain tell you what this problem is caused by. I have had this issue myself and so have others like us. Its not a vacuum leak. Its not a issue with your car, not a issue with a bad tune, not faultly install of parts. Its because we have BBK long tube headers and off road x pipe

This is a very common after affect to them. I'm betting It doesn't happen to you when the car is in drive or when stopped at a light. I bet it happens when the car is set in park and the car is idle. Let me guess, the car will idol normal and all of a sudden the rpm's drop dramatically as if the car sounds like its about to stall and then it surges back up. Been there and sometimes it still happens. Good news, nothing gonna hurt the car but must admit it can get on ones nerves.

I have Steeda, Bama, and MPT tunes and the surging issue occured with all three. After speaking on threads about this in the past, talking to AM about this surging issue as well as BBK directly, the surging idle is because of the headers. A way to combat this idle surging issue is to have your tuning company set your idle command higher, maybe like 900.

 

OP just to add, prior to figuring out what was causing my surging issue I spoke with my different tuning companies and they too said check for vacuum leaks. I did this as well and of course no vacuum leaks. I then began talking with members on various mustang forums and learned this surging idle issue affected us who have the 3.7 engine when using BBK long tube headers. Hope this helps.

 

Wow Kona I learned something new. One of my Stangs is a V6 and I had the issue with a vacuum leak. Did not know that headers could cause such an issue? Does it have the same effect on V8?

That really sucks I would not want to live with that.

 

Its my understanding from BBK, AM and others on forums this surging idle issue is effecting the 3.7 engine not 4.6 or 5.0.,

 

You are right, I do have the long Tube Headers and the off road x-pipe. Do you think that it will disappear when I install the catted x-pipes? The weird thing is I have had the pipes on for about a month and the idle surging just started this week. why not immediately after I installed the pipes and headers? Kinda sucks that this happens and they still sell this set-up for the 3.7 engine.

 

I have the BBK long tubes with the 'catted' x pipe. My idle still surges, but never dies. I live with it and it doesn't bother me

 

Have any of the Company's that are putting out the X-Pipe and Long Tube Headers, giving any reason for the Idle Surge problem? Seems strange that so many people have this problem and there is no solution for it. I don't like the idea of stalling somewhere in traffic and having to restart my engine every time.

 

See I was thinking that the catted x pipe would have the idle surging as well. The issue is the long tubes for the 3.7 with BBK. Mine never dies either but sometimes have that idle surge. I'm just used to it as well and only happens when I'm in park and car is idle. Never does it happen when load is on the engine for me.

 

I was hoping that the Catted X-Pipe would solve this problem. I guess I will wait till I get my Tuner and have the idle set up higher as suggested to eliminate the possibility of stalling.

 

That seems to be the best solution for the idle surging. Have the idle command set higher.

 

Thanks for all of the advice everybody, I'll let you know the end result.

 

I've had a drop and recovery happen in mine since I got it. Happened before and after my shorty headers. It's rather minor and rare. Not sure if it's quite what you describe, but it sounds similar.

 

Interesting, I've only heard of this issue with the long tubes from BBK but wonder if shorties are included.

 

Do you have a custom tune or a canned one? I just changed my set up yesterday and experienced more or less similar problems, after rewriting and changing the tune, the problem disappeared.