Weird idle after intake & tune... Help please

[hissingcobra]

A few days ago I installed a 127mm jlt intake and a john lund tune on my stock 2012, since i have noticed that the car idles weird and also takes a second longer to crank when starting up. When in gear and I go to neutral the rpm will go down to about 1200-1400 and stay there and then slowly go down to 750. Sometimes in neutral it will go up to 1200-1500 by itself and stay there.
Is the tune? air filter? vacuum? I have no idea what it is.

Also sometimes when driving I notice a little vibration on the clutch pedal itself and other times it does't happen.

 

[2011 gtcs]

The car has to relearn it's idle, drive it for a day or so, also as stupid as it sounds make sure there are no air leaks

 

[JLD]

Mine did the same thing and after a few days it was back to normal

 

[spitin venom]

Google the idle relearn process for the Mustang. You need to do it after the battery has been replaced (or dead) or you load a tune.
If I remember correctly...
Start the car and let it get up to normal operating temp and let it idle for 1 minute
then turn the a/c on and let it idle for 1 minute
drive the car for a few miles and it should be back to normal on the next drive cycle.

 

[hissingcobra]

Mine did the same thing and after a few days it was back to normal

how many days exactly? This has been happening for close to a week now. its very frustrating!

 

[hissingcobra]

the car just stalled, i went from gear to neutral and the rpm went completely to zero. Im thinking of resetting the battery

 

[69b302]

Make sure there are no leaks, then work with your tuner to resolve. Car should only have to learn minor corrections.

 

[Catmonkey]

If it's been idling erratically for a week with daily driving in stop and go traffic, I'd log a complaint with the tuner and let him give you a data log file to run and find out what's going on.

 

[mmmnitrous]

Had the same issue with my retune. The idle would hold 12-1500 when in neutral then slowly go down. Also popped up sometimes on its own. Drove like that for a week thinking it takes some time to relearn. Then sent a note to Lund Tuning and they sent me an alternate tune back within 2 hours... AWESOME SERVICE... Once installed runs great no more issues.

 

[DKRIPLEAN]

I had the exact problem. I would reset the computer by unhooking the battery for 30 minutes. Reattach and load the tune. Then I started it and let it idle for 1 min no a/c then 1 min with a/c. I then turned car off for about 15 mins then repeated the procedure a few more times. Then I took it out and drove it very very conservatively. I didnt get into the boost at all. I did that for a couple of days. After that I was good and no longer had the erratic idle issues. It's time consuming but well worth it.

 

[JLD]

Check the air filter make sure it is on tight

 

[PRP]

Google the idle relearn process for the Mustang. You need to do it after the battery has been replaced (or dead) or you load a tune.
If I remember correctly...
Start the car and let it get up to normal operating temp and let it idle for 1 minute
then turn the a/c on and let it idle for 1 minute
drive the car for a few miles and it should be back to normal on the next drive cycle.

The procedure is the owners manual on my 2010. I'm not sure if it's in the OM for earlier models but i'm pretty sure you have it in the quoted post.

Phill

 

[Crushinator]

It's your tune. I went through the same crap. I called Justin at VMP after dealing with all the re-learn crap, air leaks...blah blah blah. Justin's tune made the car run 100% perfect. Don't waste a month of your life like I did trying to find the solution to a problem that was obvious to me all along. No way a simple intake swap and tune should need to relearn anything.

 

[1320 Junkie]

I have a 72mm L&M on my car and didn't need a re learn of any sort...your answer has been posted already.

 

[hissingcobra]

I was able to solve the issue, thanks to the fast response from john lund. I just needed to flash the tune again and pull my air filter farther down the pipe away from the MAF and problem is solved!

 

[Silver_Serpent]

I have heard of this air filter position problem before. Obviously, the objective is to give the incoming air more time to "straighten out" (laminar flow) before hitting the MAF sensor. However, if this is such a common thing, why is the MAF sensor always located so close to the filter? Why not halfway down the tube or something. I dont know.

Anyway ... I did a TVS swap and my car didnt have to relearn anything (VMP tune at first before dyno tune).