'10 gt weird idle after rev in neutral.
 

Hey everyone! The mustang is running great, drives great, real head turner. One little issue though, it isn't causing any harm (I don't think) but would like to see if I could get to the bottom of it.

After installing my k&n cold air intake, If I'm in my driveway, and lets say I rev it to 3k or 4k, when the rpms come back down, it dips to about 100k lower then my normal idle and then immediately jumps back to normal.

For example. Lets say My idle is at 650 (just a random number). I rev the car to 2k. I let my foot off the gas. the idle does down to 550 for a split second and then immediately jumps back up to 650 like nothing ever happened.

It's not like it wants to stall or anything, just really weird. Only happens when I have the car in neutral and rev it up a little bit. It drives, upshifts, and downshifts perfectly find. (Manual tranny).

Interested what could be causing this. The k&n said the CAI doesn't need a tune, but wondering if I really do? Like it's getting to much air or something?

I would not worry about a brief 100 RPM dip.

I bet it did the same thing before, you just didn't notice and now you are paying more attention.

The change to K&N intake shouldn't affect the idle trim; and since that intake does not need a tune there is no tune change to worry about.

Could be, just by coincidence, the throttle body is a bit gummed up and sticking a little. Can't hurt to clean it.

Thats normal to my understanding that the computer is finding the new air hard to deal with so it should straighten out once learns that it has more air. At least that is how the GM's work. Call K&N they will help you.