Topic: Throttle sticking on F150

[DriverJeff]

Hi folks,

Heard a scary story from my dad the other day.  He's got a '96 Ford F150 (4.6L V8, auto) in great condition for the year -- less than 160k on it.  Anyway, the truck is used strictly for hauling the boat in and out of the lake a few times a year and for taking garbage to the dump, getting a load of soil for the garden, or carrying lumber, etc.  Real utility stuff. 

The truck lives outside throught the winter when the boat and my mom's Sonata go in the garage and last week when the large snowfall happened, he went to move it so his neighbour could plow the driveway out. 

Since it hadn't been running in a few days, he started it up and let it warm up for a few minutes (literally a few minutes) while he shovelled the sidewalk.  By the time he got in to move it, the truck was warm.

He backed it down the driveway and noticed the throttle seemed to stick a bit -- nothing too noticable -- just something a little different.  After he shifted into drive (to move up and beside the garage) he gave it a bit of gas to through the snow (25+ cm).  The truck started moving forward as expected, but when he lifted his foot off the accelerator, the revs stayed up! 

He tried braking (basically standing on the brake pedal), but with the momentum of the heavy truck, crappy old drum brakes in the rear and a fairly powerful engine, the truck overpowered the brakes easily.  Due to a large snowbank, when he tried turning to avoid the garage he was headed toward, he started to slide quite a bit.

He had the presence of mind to quickly switch off the ignition and ram the transmission into park, but not before the passenger side bumper and fender grazed the corner of the garage. 

When he went to start it up again, it was still sticking -- but the accel pedal itself moves as it should (so it's something with the throttle itself). 

My dad's no "Barrie", but he has puttered around cars for decades and feels fairl comfortable doing so.  He's quite happy using his Chilton or Haynes guides and making minor repairs -- but with this, there's nothing he can see that is causing the problem.

Does anyone have any ideas, or heard of chronic "Unintended Acceleration" problems with Fords?

This is a pretty scary situation that he'll ultimately have the dealer inspect, but if it's a common Ford problem, then he'd obviously like Ford to pay for the repairs.  Can you imagine the lawsuit Ford would have on their hands if this had happened on the highway and people had been killed?

[wing]

That sucks, but Neutral is much more friendly than park!

[Squishy]

I turned up this TSB, but for the 1997 F-150.  The closest engine to a 4.6 I can find on the 1996 was the 4.9 L I6.

1997 Ford Truck F 150 2WD Pickup V8-281 4.6L VIN W EFI

Engine - High Idle Speeds/Throttle Sticks

Article No.
98-21-10

10/26/98

IDLE - HIGH IDLE SPEEDS - THROTTLE STICKS
AFTER STEADY STATE DRIVING IN COLD AMBIENT
TEMPERATURES - VEHICLES BUILT THROUGH
12/1/97 EQUIPPED WITH 4.6L ENGINE

LIGHT TRUCK:
1997-98 EXPEDITION, F-150, F-250 LD

ISSUE
The vehicles identified in this TSB article should be equipped with an insulated PCV tube that was installed in production or under Recall 96S59. This insulation provides protection from PCV backflow due to ice in the PCV system created during steady speed driving in extremely cold weather. In those extreme cases where the insulated PCV tube does not completely eliminate throttle body icing due to PCV backflow, a service kit has been developed that will make these vehicles even less susceptible to PCV freezing.

ACTION
Verify that the condition is not caused by throttle body sludging, throttle cable binding, or interference between an improperly positioned floor mat and accelerator pedal. If no other conditions are identified, replace the PCV hose and throttle body adapter provided with the appropriate service kit. Refer to the Instruction Sheet included in the kit for installation details.

PART NUMBER (PART NAME)
F85Z-6A603-CB (Service Kit - 4.6L Romeo Engine)
F85Z-6A603-AB (Service Kit - 4.6L Windsor Engine)

OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage And Emissions Warranty Coverage

OPERATION: 982110A
DESCRIPTION: Install Service kit
TIME: 1.1 Hr.

DEALER CODING
BASIC PART NO.: 9E926
CONDITION CODE: 42

OASIS CODES: 404000, 610000, 610600, 612000, 612600, 617400, 619400

[DriverJeff]

Superb... thanks, Squishy.

And Wing, FWIW, he would've gone through N to get to P. 

[DriverJeff]

I turned up this TSB, but for the 1997 F-150.  The closest engine to a 4.6 I can find on the 1996 was the 4.9 L I6.

Come to think of it, his truck has the "5.0" 302ci I believe, not the 4.6. 

[rrocket]

Sometimes when it gets cold then warm and so on, moisture can freeze the cables up some.  Sometimes the greases itself can be sticky when it's very cold.  Likely a good cleaning of the cable and throttle body linkage and butterfly might do the trick.

[Cord]

I turned up this TSB, but for the 1997 F-150.  The closest engine to a 4.6 I can find on the 1996 was the 4.9 L I6.

Come to think of it, his truck has the "5.0" 302ci I believe, not the 4.6. 

Yes it does. The 4.6 did not appear until the new model in 1997.

[Squishy]

No similar TSB for the 1996 with a 302.  I was hoping you got the year wrong instead of the engine, as that other TSB seemed too perfect.  Now you'll just have to follow the throttle cable and cruise control cable and look for any kinks or obstructions.  Clean the throttle body as well, and the IAC valve if it's accessible.  Try to move the butterfly valve with your hand with the engine off and see if there is any extra resistance that may be the cause.

If nothing obvious can be found, just clean everything good and lube it up much like you'd do with the brake lines on an old bike.

[barrie1]

I would sincerely recommend a can of Injector spray with the cleaner already in it. You will clean the inside and outside of the throttlebody area and the linkage on it as well. Never spray WD40 on the linkage as it attrach more dirt and  the problem will only get worse and be more frequent as well. Even Canadian Tire has some good sprays to use but try to get the one that does both jobs at once. Clean and lube.  Unfortunately they have had some problems with the Ford engines where they stick like this especially on the 302 design. I think the throttlebody gums up and causes these probelms after sitting for a while but is easily rectified by doing this type of maintenace.