Hanging RPM's while shifting.

[67HotRod]

My 02 GT takes about 3 seconds to go from 3000 down to 1000 between shifts. Is this normal? Surely the motor isn't that loose after 11,000 miles??
Thanks

 

[mhanna77]

I think this is very common or even "normal" for the Stangs. It annoys the crap out of me. I bought and installed an item between the IAC and intake called something like the Idle Control Kit, according to an archive it was suggested to fix the problem. No luck, when you examine the part it isn't even possible for it to work. In fact the directions said it was to fix a 5.0L throttle stick problem.
I did however unplug the IAC and adjust the throttle stop screw to bump up the idle.
Up Side= No more hanging RPM's, exhaust sounded real mean between shifts, car ran normally.
Down Side= Check engine light stuck on, when I turned the A/C on it tried to stall the engine because the IAC wasn't plugged in to adjust the idle. and who knows what else.

 

[Joltergeist]

What you'll need to fix that is an aluminum flywheel.

 

[mity2]

What you'll need to fix that is an aluminum flywheel.

100% agree with Mhanna77
It is actually a very common "Ford thing". what it is is that Ford somehow thought that when you let go the gas pedal, there is enough gasvaper left in the combustion chamber that if enough air is not getting to it, it'll not burn compleatly. Hense bad emmission.
Soooooooo Mr. Smarty pants at Ford thought "well, then We'll let Idle Air Control Valve to stay open for a while, which will promote complete combustion"

My 00 Focus does it, my 99 Cougar did it, and so is the Stang.

On my Cougar, THFIX(as we called it on N.E.C.O.) was to "Chock" the air line goes in to intake from IAC valve. But probrem with it is that I tghink it also act as idle up for A/C as well, there for when you choke the line, which pretty much eliminate the probrem of th hung, also couses probrem while A/C is on. Basically when A/C is on, and as RPM come down, there is not enough air going to intake and car will... well, stall..

Light weight flywheel will help some what, but not much. you still have sluggish feel. At least on my Cougar, Fidanza Flywheel didn't help much

 

[stang9gt]

An aluminum flywheel will help but it will also take away torque for drag racing...If u r into street racing or auto cross an aluminum flywheel is the way to go cause it will rev faster...

 

[67HotRod]

I think this is very common or even "normal" for the Stangs. It annoys the crap out of me. I bought and installed an item between the IAC and intake called something like the Idle Control Kit, according to an archive it was suggested to fix the problem. No luck, when you examine the part it isn't even possible for it to work. In fact the directions said it was to fix a 5.0L throttle stick problem.
I did however unplug the IAC and adjust the throttle stop screw to bump up the idle.
Up Side= No more hanging RPM's, exhaust sounded real mean between shifts, car ran normally.
Down Side= Check engine light stuck on, when I turned the A/C on it tried to stall the engine because the IAC wasn't plugged in to adjust the idle. and who knows what else.

Thanks, as bad as that is, it makes sense. You'd think they could find a way around that in the programming somehow. Oh well. At least it's not simply as loose as I was afraid it might be, I bought it used

 

[Ryan L]

An aluminum flywheel will help but it will also take away torque for drag racing

Not true. MM&FF tested one last year and it both gained power on the dyno and ran a quicker 1/4 time.

 

[silver4.6]

1/2 copper pipe cap will fit just right in the IAC hose, all you have to
do is drill a 3/16th hole in the cap to allow some air to pass (or adjust the hole size to adjust the throttle drop). The cap only costs about .40
and it will fix your throttle hang.

 

[X-Firechicken]

this works

1/2 copper pipe cap will fit just right in the IAC hose, all you have to
do is drill a 3/16th hole in the cap to allow some air to pass (or adjust the hole size to adjust the throttle drop). The cap only costs about .40
and it will fix your throttle hang.

I can vouch for the fact that the copper pipe cap works but if you make the hole too small, it will cause the IAC to fail and throw an SES light. My IAC failed with a 3/16 hole. I found a 5/16 hole worked well, but when the engine is cold, it tends to stumble a bit on accelleration from a dead stop.

 

[Winston]

You may want to change the dashpot settings but you will need a chip (maybe a 4 banker chip) or a reflash to implement them.
I have made these changes among others to my 02GT 5spd and no more flaring and hanging of the engine speed.

 

[TL GT]

Does anybody have a picture of where exactly the copper plug goes?In the other picture it's too close-up to tell exactly.Also,what do you do with the vacuum line that gets taken off?Leave it hang there or put a plug in that also?

 

[Winston]

You probably use the copper cap as a restriction for the air coming down the hose. The hose must go back on or you could get a MIL.

 

[Blev]

You probably use the copper cap as a restriction for the air coming down the hose. The hose must go back on or you could get a MIL.

The thread resurrect uhhh er has struck!! Has anyone else done this? I can’t see the pictures that were posted. Anyone have pix where I can see where the cap goes?

 

[warment]

I had this same problem some time ago. I did some testing of the sensors on my car and found that the DPF-something (Differential Pressure Feddback) sensor went bad. If you have a Hayes manual, the sensor is mentioned. It is a little black square sensor that sits on the back side of the intake if I remember correctly...

Bill

 

[daver01]

i thought my steeda pulleys helped my car drop rpm quicker. not drastic, but every bit helps.

 

[Blev]

Still looking for a picture of where to put the cap.

 

[adamb258]

Still looking for a picture of where to put the cap.

ME too!

 

[GoldnGT]

I've been looking for one for a long time... noone will post one.. =o\

Mike

 

[adamb258]

I've been looking for one for a long time... noone will post one.. =o\

Mike

Why Not? Someone has to have the time/capabilities to do this for a few fellow stangers! Right?

 

[Turbo92PGT]

My car does it. It pisses me off. it seems to be doing it more lately. I wonder if my throttle is sticking. Say you're cruising and let off the gas, a good 2-3 seconds later you will feel/hear the change in rpm. Its like it continues to go for a whlie longer.