Variable runner intake manifolds?

I took my car back to my tuner a couple of days ago because it felt like my car was surging. When u roll your foot into the throttle, its starts to hesitate. If u floor it no problem. It goes. He said something about the variable runners on the intake manifold. He said it's something he can't adjust. It's new on the 15s. Said it might get worse with the more power I make. Anybody else have this problem? It's kind of hard to explain. Roll into the throttle don't floor it and the car feels like it's pulling back for a second then speeds up without adding extra throttle. We took it for a drive, he plugged it up to the computer and he could see the surge in the graph but said he can't open that table yet smh.

Who is your tuner? Sounds like you need a new one.

Mine does it a little in certain part throttle accels but I also have noticed surging on other fly by wire cars. I heard by installing a pedal max that will fix it but I haven't verified it personally if it does...I'm Steeda tuned by the way

Mine does it the worst when the engine is cold.

This may be the culprit to what I'm experiencing, as well.

http://www.mustang6g.com/forums/showpost.php?p=666292

robmustang201528 said:

Mine does it the worst when the engine is cold.

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Same here!

carsontech said:

Same here!

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Who tuned your car

Nobody. Mines stock.

carsontech said:

Nobody. Mines stock.

Click to expand...

And your car runs crappy when cold?

Not "crappy", exactly, just that my issue is more noticable when the engine is cold.

Very weird. My car ran like shit only after tuned that's why I asked.

I'm still having this issue and it bother me that I'm having this problem with a new car. Talked to alot of people at mustang week and there not having this issue. Talked to my tuner and he's saying there's nothing he can do about it. I hate to start putting a bunch of different tunes in my car from different tuners but I don't know what to do. I don't know if that will mess up anything or not but I want this problem fixed. Ford or anybody for right now isnt coming out with any new intake manifolds .What should I do?

Yes the car has variable length intake runners, my GT is still stock so I cannot speak about a tuned motor too much, but it would seem that most of the "big name" tuners aren't having much trouble tuning around it.


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If I were you I'd return it to stock and get an email tune from one of the reputable tuners on this site. Sounds like the tuner you're using doesn't know how to tune the S550.

Which one would u recommended?