Idle issue nightmare
Cargo Master
Joined: Jun 2013
Posts: 3,182
Likes: 15
From: Somewhere n North America
The Malfunction Indicator Light (MIL) / MIL (Check Engine Light/CEL) did not start until 1988.
Prior to this is the Inferred Mileage Sensor (IMS) / Emissions Light.
See attached TSB;
Prior to this is the Inferred Mileage Sensor (IMS) / Emissions Light.
See attached TSB;
Lead Driver
Joined: Feb 2002
Posts: 7,972
Likes: 596
From: Greater Austin, Texas
Have you tried unplugging the IAC? If the extra air is not coming via the IAC, or the throttle blades, then you have a vacuum leak.
The Speed Density system on your truck will interpret any extra air as you opening the throttle, and it will pump in more fuel accordingly.
The Speed Density system on your truck will interpret any extra air as you opening the throttle, and it will pump in more fuel accordingly.
Cargo Master
Joined: Jun 2013
Posts: 3,182
Likes: 15
From: Somewhere n North America
Another thing you need to check is your TPS output voltage.
Output to ECA is the Dark Green/Light Green stripe wire;
Also check the TPS reference voltage, Orange/White stripe wire.
Output to ECA is the Dark Green/Light Green stripe wire;
Also check the TPS reference voltage, Orange/White stripe wire.
Lead Driver
Joined: Oct 2016
Posts: 6,185
Likes: 633
From: Houston/Sugar Land
ok Thanks -I have tried numerous times to run codes with a obd 1 scanner & the jump wire method --no luck Ill keep plugging away --Thx for your reply
Do you have a manual or auto transmission? If manual, your clutch must be depressed the entire time while doing the codes.
Do you have a manual or auto transmission? If manual, your clutch must be depressed the entire time while doing the codes.
Thread Starter
|
Cross-Country
Joined: Sep 2018
Posts: 95
Likes: 0
ok Thanks -I have tried numerous times to run codes with a obd 1 scanner & the jump wire method --no luck Ill keep plugging away --Thx for your reply
Do you have a manual or auto transmission? If manual, your clutch must be depressed the entire time while doing the codes.
Do you have a manual or auto transmission? If manual, your clutch must be depressed the entire time while doing the codes.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Fords to Drive Before You Die
Joe Kucinski
3 Best / Worst Features Of The 2025+ Ford Expedition
Brett Foote
10 Ways Ford is LOSING to the Competition
Joe Kucinski
Top 6 Best Deals Available on New Fords & Lincolns Right Now
Brett Foote
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Verdad Gallardo
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
Cargo Master
Joined: Jun 2013
Posts: 3,182
Likes: 15
From: Somewhere n North America
I learned that from you as well.....
Lead Driver
Joined: Oct 2016
Posts: 6,185
Likes: 633
From: Houston/Sugar Land
. I would think you should be able to do both the light or the reader. The $20 Innovava reader most of us use has an extension available so you can sit in the driver's seat and use it checking codes while having the clutch depressed.
Cargo Master
Joined: Jun 2013
Posts: 3,182
Likes: 15
From: Somewhere n North America
I doubt you have a CEL.
Is your light Red? that would be a Engine Warning Indicator for the Oil Pressure & Coolant Temperature.
CELs are usually Yellow/Orangeish
You may also have a "Emissions" light.
See what lights up when you first turn your Key on.
Now, your could very well have some 1988 technology in her if she is a late in the year build date.
Check your Build date/MFG Date on the sticker inside the drivers door.
Cargo Master
Joined: Jun 2013
Posts: 3,182
Likes: 15
From: Somewhere n North America
This is what it looks like. I'll bring it back up after you get through all the other suggestions. I might not remember it for three months for all I know.