Idle problem, RPMs keep increasing! - '00 GT - Ford Mustang Forum
 
LinkBack Thread Tools
post #1 of 9 (permalink) Old 08-20-2013 Thread Starter
PONY Member
4.6L Member
 
danieljag1's Avatar
 
Joined: Jan 2011
Location: Spring Hill
Posts: 343
 
Idle problem, RPMs keep increasing! - '00 GT

I have a 2000 GT, 168k, 5sp. Just the other day I was coming to a stop in my driveway after work and I noticed my RPMs weren't coming down to normal idle. They were around 1300rpm. I tried revving to see what would happen and they just kept increasing and wouldn't come back down! I had to just shut off the car and I'm afraid if I shut it off when it's revving to high I might damage the internals. This happened again tonight so I'm looking to have this fixed right away.
I was thinking maybe a bad TPS? IAC is fairly new, less than a year old. I haven't cleaned MAF in a while, I'll try that too. Any other possible culprits?
Thanks guys!

2000 Mustang GT!!!
FRPP Intake manifold, Flowmaster 40's with larger pipes and tips (Nice deep tone).

"I want to own a shop where people can come and not get completely ripped off" - Ludacris (Fast Five)
danieljag1 is offline  
Sponsored Links
Advertisement
 
post #2 of 9 (permalink) Old 08-20-2013
GT Member
 
newponyboy04's Avatar
 
Joined: Aug 2012
Location: Sierra Vista
Posts: 1,577
 
Check the iac, throttle body and any vacum leaks

a man's most expensive hobby started with a 97 cent hotwheels

1999 saleen s281sc vert 11k miles #261/421 built 1/170 vert 1/10 exact combo
2000 Roush v6 sport 78k miles
newponyboy04 is offline  
post #3 of 9 (permalink) Old 08-20-2013 Thread Starter
PONY Member
4.6L Member
 
danieljag1's Avatar
 
Joined: Jan 2011
Location: Spring Hill
Posts: 343
 
Quote:
Originally Posted by newponyboy04 View Post
Check the iac, throttle body and any vacum leaks
I know for a fact that it isn't my IAC. I will check for vacuum leaks and clean the MAF and throttle body.

2000 Mustang GT!!!
FRPP Intake manifold, Flowmaster 40's with larger pipes and tips (Nice deep tone).

"I want to own a shop where people can come and not get completely ripped off" - Ludacris (Fast Five)
danieljag1 is offline  
post #4 of 9 (permalink) Old 08-20-2013
GT Member
 
newponyboy04's Avatar
 
Joined: Aug 2012
Location: Sierra Vista
Posts: 1,577
 
I know you said the iac isnew but make sure its not a defective one.

a man's most expensive hobby started with a 97 cent hotwheels

1999 saleen s281sc vert 11k miles #261/421 built 1/170 vert 1/10 exact combo
2000 Roush v6 sport 78k miles
newponyboy04 is offline  
post #5 of 9 (permalink) Old 08-20-2013
SHELBY GT 350 Member
Classic Member
4.6L Member
 
SoCal2V's Avatar
 
Joined: Sep 2010
Location: Hell
Posts: 6,649
 
While experiencing the issue, unplug the IAC electrical connector. What happens? If the engine stays running, go buy a new one - Motorcraft if at all possible (check rockauto, they usually have oem stuff like this and prices usually don't make your piss boil).

Being that the Idle Air Control does just exactly as it's name implies, I'm leaning on that for now. Vacuum leaks usually produce a low unsteady idle, and TPS are rare to have issues and generally have different symptoms when they do. As far as replacement IAC's, I've heard before that certain brands sold by parts stores aren't destined for greatness, so I'm kinda thinkin that's what's happening to you.


2001 GT Convertible

All the usual bolt-ons
1967 Coupe
200 I6, C4
SoCal2V is online now  
post #6 of 9 (permalink) Old 08-20-2013
SHELBY GT 350 Member
4.6L Member
 
racin366's Avatar
 
Joined: May 2008
Location: Pompano Beach
Posts: 5,340
 
Start by checking the throttle return spring at the throttle body! Its probably not the problem, but you need to be certain of that before anything else. I would even check the cruise control stuff, the rpm's climbing and not coming back down is not a common problem and definitely serious.

If the revs are climbing and you can't stop them shutting it down is the best thing you can do. The spark and fuel are cut off, but as long as the engine turns the oil and water pump turn so you will do less damage than anything else you could do.

As as most things for your Mustang go the aftermarket is better and costs less than stock. In terms of sensors, OEM is the only way to go.

The artist formerly known as SteedaMatt.
racin366 is offline  
post #7 of 9 (permalink) Old 08-20-2013
Rookie
 
2000 Mustang GT's Avatar
 
Joined: Dec 2010
Location: Farmington
Posts: 48
 
It's a small crack in the vacuum lines. I had the same problem! Visually inspect the line from the firewall all the way to the throttle body and fuel solenoid.

Crystal White GT- 2003 Mustang gt swapped engine, TR-3650 swapped transmission, BAMA SCT Tuner, K&N CAI, BBK 75mm throttle body, RPM Upper Plenum, Typoon Intake Manifold, BBK Short-Tube headers, BBK O/R X-Pipe, American Thunder Flowmasters, 3.73 gears, H&R Lowering Springs, Saleen Wheels
2000 Mustang GT is offline  
post #8 of 9 (permalink) Old 08-23-2013 Thread Starter
PONY Member
4.6L Member
 
danieljag1's Avatar
 
Joined: Jan 2011
Location: Spring Hill
Posts: 343
 
Thanks for all of the replies guys! It hasn't happened since I posted this thread so we will see how it plays out! Definitely unplugging the IAC will be the first thing I try. I did buy Motorcraft so hopefully it isn't a defective.
It makes me feel a little better knowing that shutting it off is the best thing to do.

2000 Mustang GT!!!
FRPP Intake manifold, Flowmaster 40's with larger pipes and tips (Nice deep tone).

"I want to own a shop where people can come and not get completely ripped off" - Ludacris (Fast Five)
danieljag1 is offline  
post #9 of 9 (permalink) Old 09-14-2013 Thread Starter
PONY Member
4.6L Member
 
danieljag1's Avatar
 
Joined: Jan 2011
Location: Spring Hill
Posts: 343
 
Well guys it happened again tonight...I did what you said and unplugged the IAC and the engine reminded running. The idle went WAY down though. I went from sitting at 2300 to 500-650 until I finally shut off the car. I will be checking my receipt for the warranty on it.


Sent from AutoGuide.com Free App

2000 Mustang GT!!!
FRPP Intake manifold, Flowmaster 40's with larger pipes and tips (Nice deep tone).

"I want to own a shop where people can come and not get completely ripped off" - Ludacris (Fast Five)
danieljag1 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Ford Mustang Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a VALID email address for yourself, otherwise you will not receive the necessary confirmation email needed to confirm, validate and activate your new AFM member account.

Failure to provide a VALID email address, will result in the cancellation of your new AFM member account registration.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183