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  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

Hanging RPM's while shifting.

  • Thread starter Thread starter 67HotRod
  • Start date Start date Aug 29, 2003
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67HotRod

New Member
Aug 19, 2003
27
0
0
SW MO
Aug 29, 2003
#1
  • Aug 29, 2003
  • #1
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

Member
Jul 24, 2003
159
0
16
Cincinnati, Ohio
Aug 30, 2003
#2
  • Aug 30, 2003
  • #2
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

Founding Member
Jun 24, 2002
50
0
0
Northern VA
Aug 30, 2003
#3
  • Aug 30, 2003
  • #3
What you'll need to fix that is an aluminum flywheel.
 

mity2

I like Pro3 and all I got was this crappy CT.
Jul 24, 2003
2,872
3
48
StateCollege PA
Aug 30, 2003
#4
  • Aug 30, 2003
  • #4
Joltergeist said:
What you'll need to fix that is an aluminum flywheel.
Click to expand...

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

Founding Member
Dec 21, 2001
1,247
0
0
State College, Pa
Aug 30, 2003
#5
  • Aug 30, 2003
  • #5
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...
 
6

67HotRod

New Member
Aug 19, 2003
27
0
0
SW MO
Aug 30, 2003
#6
  • Aug 30, 2003
  • #6
mhanna77 said:
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.
Click to expand...

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
 
R

Ryan L

Founding Member
Apr 15, 2001
783
0
16
St. Augustine, FL
Aug 30, 2003
#7
  • Aug 30, 2003
  • #7
stang9gt said:
An aluminum flywheel will help but it will also take away torque for drag racing
Click to expand...

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

silver4.6

Founding Member
Apr 11, 2001
514
0
16
In a little concrete bunker.
Aug 31, 2003
#8
  • Aug 31, 2003
  • #8
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

X-Firechicken

New Member
Apr 2, 2003
32
0
0
Phillipsburg, NJ
Aug 31, 2003
#9
  • Aug 31, 2003
  • #9
this works

silver4.6 said:
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.
Click to expand...

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.
 
W

Winston

Founding Member
Feb 16, 2002
136
0
0
Stone Mountain, GA
Aug 31, 2003
#10
  • Aug 31, 2003
  • #10
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.
 
T

TL GT

Founding Member
Jul 11, 2002
89
0
0
Dearborn
Aug 31, 2003
#11
  • Aug 31, 2003
  • #11
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?
 
W

Winston

Founding Member
Feb 16, 2002
136
0
0
Stone Mountain, GA
Aug 31, 2003
#12
  • Aug 31, 2003
  • #12
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

New Member
Aug 17, 2003
1,295
1
0
So. Cal. V-Town
Apr 1, 2004
#13
  • Apr 1, 2004
  • #13
Winston said:
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.
Click to expand...

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

Founding Member
Aug 23, 2000
339
0
0
Spotsylvania, VA
Apr 1, 2004
#14
  • Apr 1, 2004
  • #14
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

Founding Member
Oct 4, 2002
396
0
0
Lexington, Ky
Apr 1, 2004
#15
  • Apr 1, 2004
  • #15
i thought my steeda pulleys helped my car drop rpm quicker. not drastic, but every bit helps.
 

Blev

New Member
Aug 17, 2003
1,295
1
0
So. Cal. V-Town
Apr 10, 2004
#16
  • Apr 10, 2004
  • #16
Still looking for a picture of where to put the cap.
 
A

adamb258

New Member
Mar 30, 2003
300
0
0
dallas
Apr 13, 2004
#17
  • Apr 13, 2004
  • #17
Blev said:
Still looking for a picture of where to put the cap.
Click to expand...


ME too!
 

GoldnGT

Founding Member
Aug 21, 2002
427
0
0
Birmingham, AL
Apr 13, 2004
#18
  • Apr 13, 2004
  • #18
I've been looking for one for a long time... noone will post one.. =o\

Mike
 
A

adamb258

New Member
Mar 30, 2003
300
0
0
dallas
Apr 13, 2004
#19
  • Apr 13, 2004
  • #19
GoldnGT said:
I've been looking for one for a long time... noone will post one.. =o\

Mike
Click to expand...

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

Turbo92PGT

Member
Feb 17, 2003
746
0
16
Auburn Washington
Apr 13, 2004
#20
  • Apr 13, 2004
  • #20
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.
 
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