Notices
1987 - 1996 F150 & Larger F-Series Trucks 1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks

High idle problem

Thread Tools
 
Search this Thread
 
Old Jan 26, 2021 | 09:44 PM
  #1  
jason90f150's Avatar
jason90f150
Thread Starter
|
Mountain Pass
Joined: Apr 2015
Posts: 223
Likes: 0
From: Colorado
High idle problem

89, Bronco 5.0 AT. While driving today the idle went up to about 1400. Was working fine until then. When I'm in drive, it idles around 1000. I didn't want to drive around with the IAC unplugged. When I unplug it, works fine. Its brand new, only 4 drive cycles on it. I just put in reman engine, transmission, rebuilt transfer case, rear axle, etc. Basically everything under the body. Should I just replace the IAC? Its been awhile since I've had an issue, 1st time back on forums in years...
 
Reply
Old Jan 26, 2021 | 10:54 PM
  #2  
Conanski's Avatar
Conanski
FTE Legend
15 Year Member
Photogenic
Photoriffic
Community Builder
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
Have you pulled codes?
Is the throttle cable sticking?
Verify the throttle blades are closing correctly.
 
Reply
Old Feb 27, 2021 | 11:15 PM
  #3  
andywould90's Avatar
andywould90
New User
Joined: Nov 2020
Posts: 16
Likes: 0
My 88 f150 started doing that after i replaced my iac and im not sure why but i started throwing egr codes dont remember which ones but i just went ahead and replaced egr valve, evp and the egr solenoid you can test the valve with a vacum pump just remove vacuum hose from evp which is screwed to the top of egr valve on left side of intake and apply vacuum and see if diapham shaft moves up diaphram should also hold vacuum if not valve is bad if valve is good then test evp circuit remove connector take multimeter with ignition in run position test reference voltage evp harness connector pin should be between 4 and 6 volts id check for vacuum leaks as well good luck
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Frank79
2017 - 2022 Super Duty
3
Dec 11, 2019 07:35 PM
Michael Ward
1997 - 2003 F150
16
Apr 17, 2019 11:36 AM
JEV
1987 - 1996 F150 & Larger F-Series Trucks
17
Jun 9, 2005 08:28 PM
robpro
1978 - 1996 Big Bronco
2
Jan 21, 2005 10:41 AM
bigric
1978 - 1996 Big Bronco
5
Jul 7, 2003 11:53 AM




All times are GMT -5. The time now is 05:26 AM.

story-0
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-1
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-2
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-3
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-4
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-5
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-6
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-7
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-8
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-9
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE