Slow Return To Idle

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Sep 23, 2004 | 11:48 AM

aerocolorado

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Slow Return To Idle

Greetings from your newest Ranger owner. While I am intimately familiar with the 4.0L engine, this Ranger is a 98' 3.0L with 83,000 miles, manual transmission. I have search this forum and the 3.0 for this problem without success. After warmup, the engine is slow to return to idle, staying around 2500 rpm for around 10-15 seconds before dropping to 1000. Im familiar with the antics of the IAC valve but this does not seem to behave like that. I suspect the EGR system but am not certain. Any hints?

Sep 23, 2004 | 12:41 PM

CowboyBilly9Mile

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From: Eastern WA

I'd first inspect vacuum lines for damage, etc, then proceed to pull any codes.

Sep 23, 2004 | 01:18 PM

Mike W

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Joined: Apr 2002

Posts: 7,157

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From: Central Kali

Every day I pull off the freeway at 70. I then stop at the end of the off ramp. While waiting to make a left turn, I notice my tach is around 2000 rpm. I only see this happen during this stop, never just driving around town in my 01, 4.0.

Sep 23, 2004 | 01:35 PM

Rockledge

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Joined: Jan 2003

Posts: 9,748

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From: Connecticut

Check to see if your Ranger is covered by this TSB:

Quote:

Article No. 98-26-8

• IDLE—HIGH IDLE SPEED (1300-2000 RPM) DURING
CLOSED THROTTLE DECELERATION WITH THE
TRANSMISSION IN NEUTRAL OR WITH THE
CLUTCH DEPRESSED
• MALFUNCTION INDICATOR LAMP (MIL)—MIL
ILLUMINATED WITH DIAGNOSTIC TROUBLE CODE
(DTC) P0320 STORED IN MEMORY
• LAMP—MALFUNCTION INDICATOR LAMP (MIL)
ILLUMINATED WITH DIAGNOSTIC TROUBLE CODE
(DTC) P0320 STORED IN MEMORY

FORD: 1998-1999 RANGER

CALIBRATION
8-49A-R06, 8-49B-R10, 8-49S-R10, 8-49T-R06,
9B1M-AA-A, 9B1M-AB-A, 9B1M-AC-A, 9B1M-BA-B,
9B1M-BB-B

WARNING
THIS MODIFICATION IS AUTHORIZED ONLY FOR
THE LISTED ENGINE(S). PERFORMING THIS
MODIFICATION ON OTHER ENGINE
CALIBRATIONS IS UNAUTHORIZED AND COULD
CREATE LIABILITY UNDER APPLICABLE
FEDERAL OR LOCAL LAWS.

ISSUE
The Malfunction Indicator Lamp (MIL) may
illuminate and Diagnostic Trouble Code (DTC)
P0320 may be stored in memory on some vehicles.
There may also be a high idle rpm (1300-2000) on
closed throttle deceleration in Neutral or clutch
depressed. This may be caused by the Powertrain
Control Module (PCM) calibration.

ACTION
Reprogram the PCM to latest calibration level. This
more robust calibration reduces deceleration air flow
and reduces the possibility of high rpm with high
limit hardware. In addition, the calibration error is
fixed to reduce the possibility of unique driver action
causing a false P0320 MIL code.
Obtain an Authorized Modifications Decal (FPS
8262 - obtainable through DOES II, 25/pkg) and list
the date, dealer number, and summary of
modifications performed. Select a prominent place
adjacent to the Vehicle Emission Control Information
Decal suitable for installing the Authorized
Modifications Decal. Clean the area, install the
decal, and cover it with a clear plastic decal shield.

OTHER APPLICABLE ARTICLES: NONE

WARRANTY STATUS: Eligible Under The
Provisions Of Bumper To Bumper Warranty Coverage
And Emissions Warranty Coverage

Sep 23, 2004 | 03:22 PM

Mike W

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Joined: Apr 2002

Posts: 7,157

Likes: 1

From: Central Kali

For some reason I feel that Bill Gates is controlling our trucks. Yeah, we know there is a bug in the software; we will do a patch later.

Sep 23, 2004 | 05:32 PM

aerocolorado

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Rockledge, thanks for the TSB info. Will do some checking on this.

Sep 23, 2004 | 05:47 PM

maticuno

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Joined: Nov 2003

Posts: 2,107

Likes: 3

From: California Desert

If you aren't getting a check engine light, I would suspect a faulty connection in the Throttle Position Sensor wiring harness. There is a TSB about this fix too, but I don't have it available. I had the same problems you are experiencing and I seem to have at least temporarily fixed it by cleaning and fidgeting with the wire harness.